Roger Is Stumped by This Tricky Problem. Can You Help?
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- Äas pĆidĂĄn 22. 08. 2024
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Roger cannot figure out why Ryan has moisture under his floorboards.
Here's the message from Ryan:
Hi I love your channel and find it really insightful hence why Iâm here, I have a problem within my 1930âs detached house.
As you can see from under the floor in the front of the property itâs soaking and to be honest Iâm worried.
Inside of the cavity in the bay window has no insulation no where in the property does but I can see beads of condensation on the bricks.
Please help. Thank you.
=================================
#HomeImprovement #damp
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As a retired Building Surveyor I believe this is classic signs of condensation. North facing wall and insufficient ventilation to the floor void is the cause. More crossflow ventilation is required to the underfloor void. Also clear the stuff you are storing down the side of the house away from the wall. It also appears that your bay window is solid 9" or 225 mm if this is the case then cold bridging will be taking place. You will need to insulate this area of wall to reduce this cold bridging. I hope this helps.
If itâs not a leak, Iâm with you. All the surrounding areas are warmer, so this area has become the dew point. I would have designed for air bricks at nearer 1200 centres.
I hope we find out in due course.
Yes, I'm with you on this.
There should be crossflow.
Two vents to the front and two to the side isn't sufficient crossflow in my opinion.
There needs to be vents at the rear as well.
Oh yes I concur with your diagnosis. Although I havenât got a clue whatâs going on.
Iâd say the cavity is full of cement thatâs fallen from the back of the exterior brickwork thatâs blocked the vents and therefore preventing the through flow of air. There looks to be enough vents to provide sufficient air flow. There does look to be a cavity in the bay window but cold bridging could also happen as a consequence of a debris filled cavity.
If that being the case coral boy why hasnât this showed up before many years ago how long has the rear extension been put there would be an indication of the problem that itâs going on now Donât you think and the timbers would have rotted already I think this is something more recent but what I donât know many thanks
It's great! My shed has been completed and it turned out nice looking and sturdy and it is way better than the sheds that many of my neighbors had put up. Of course, I'm pleased with the outcome and this Ryan's czcams.com/users/postUgkxGZedDTcDfgD7fG_uU4esfx_EgxzlY2_1 Plans was extremely useful to me as a guide.
Be worth smoke checking the draught from the front air brick(s) to the side - at least that would give you an idea of air movement. Second thing would be to stick a moisture probe into the subfloor to check for any upflow of water - might be simply (đ) a broken terracotta drain/feed.
Just to be 100% sure (if you have a water meter) isolate everything in the house, leave it off for as long as possible and see if the meter accumulates.
That's really wet under there. I'd be pressure testing incoming water main and surface water drainage. I think if sewer leaking you'd probably be smelling it.
Any chance of a follow-up on this case?
This is a simple ventilation issue as Roger suggests but exacerbated by the vinyl flooring and plastic external paint. It's nothing to do with the damp course so injection will make no difference. The humid air rises but can't escape upwards due to the flooring or outwards due to the paint so it condenses on the cold bay. The only answer is cross ventilation (you have to exhaust that damp air) as Roger says, either with more vents or - as I did - rig up a fan and timer underneath venting outside somewhere. It'll take a few months to dry out but it's feasible.
That is exactly it. The vinyl flooring acting like a dpc, but on top of the timber that itself would normally breathe.
I had a similar problem with a north facing house. It turned out to be condensation caused by a combination of gaps under the skirting and central heating pipes routed under the floor. The central heating warming and cooling under the floor with the warm air getting drawn under the skirting caused dripping condensation. It was soaked, the end result was routing the heating above the floor, 5 new joists, and skirting fitted on a 10mm foam bed to seal the floor. All good now bone dry 6 months later.
Possibly a leaking drain making ground wet. In my previous property there was a retrofitted manhole over the original clay drain that had settled and cracked the pipe at entry/exit, leading to long term leak resulting in damp, rotten joists and localised subsidence. Drain survey can help determine if this is the case.
It could also be an old lead water main leaking. If you donât want to take the floor up a boroscope would help. Also if itâs not a combi boiler and a heating pipe is leaking, it wouldnât trip the boiler on low pressure, the f & e tank could be topping up.
I've seen his type of floor construction before on my own house which is also on clay. One half being traditional suspended timber with another part being concrete. What we had discovered is due to heave with the clay the building had a bit of subsidence on one side and when they built an extension out of the back with a concrete slab they also poured and 'filled in' a few rooms worth of suspended floor to 'fix' it.
This meant the house lacked proper front to back ventilation along the length of the joists and it had a very small gap under joists so our solution was to put a comical amount of air bricks in. Solved the problem.
This looks very wet though even with clay and with big air bricks. I'm wondering if there is a leaking pipe? After all damp like that would have rotted those joists sooner so I would be looking for something that has changed. Water bills higher than they were?
agree on leaking pipe maybe why heater didn't heat well or drif pipe
Exactly my thoughts, does the water main run under that room and leaking?
yeah, surely there has to be a mains water pipe, radiator or waste pipe etc leaking. it could also be the chimney and old under floor vent for the fireplace channeling water under the floor.
My 1st guess would be a old lead pipe which is still live, but not servicing anything, had one at the back of my house, came up from under the original footings, it was sat in clay very slowly weeping (like damp), once it was disturbed, lots of little pin holes were visible, House is 100 years old.
Do the smoke test to see how the air is moving through the house...if it even is.
Hi Roger, great video. Just wanted to say that i come across this kind of thing regularly each winter. The chap is giving all the clues without knowing it! The problem areas is north facing so is already going to be colder therefore more of a dew point for humidity.sub floor ventilation seems to be rather lacking as you clearly deduced. I often see this type of issue when there has bee a break in the through flow of air by way of extension or similar. As you know Roger, I am a PIV specialist and as another viewer has written, it is a certainty that the installation of a PIV would make all the difference here. It would force the issue of ventilation - this is now needed as the flow is now none existent since the extension.
The chap seems to have a northern accent and if the property is close to us in the north I would be happy to take a closer look. Would love to help out on this one!
Force the issue of . It's under the floor. I've never heard of using a PIV unit under floor!!
@@mmac-fr5xu doesnât matter - the PIV if designed and sized correctly will pressurise the floor void though fabric weaknesses
@@steffananthonyholden2752 Bs. You never heard of floor coverings. Carpets,laminate,vinyl !!
@@steffananthonyholden2752 Bs. You never heard of carpets,laminate,vinle flooring ? I'd of thought they'd make the floor airtight!
definitely there is an issue with ventilation. Check those old air bricks if they are clean or even if they are going under the floor, because sometimes they are going just to the cavities. And consider to replace them with a new one that will go through cavity under the floor and add some more around the house. People are living in the houses differently from the past. They don't use fireplaces which cause strong drag and better air flow. Old floor boards have gaps between them, so ventilation was better. Now days when everything is sealed you need to add ventilation at some point.
Agreed, the fireplace/ chimney being damp is worth investigating too. The floor should come out. Or at least put and air vent at the front or to the side of the hearth. Perhaps a hit/miss brass floor vent. When the fire is burning it will help draw air from the vent through the void and up the chimney. Obviously, there is another issue causing the damp but it could be more controlled.
definitely?
Looks more like a leak under there.
@@vladimirputin4822 Yes, it could be leak. Could be high level of underground water after rains. There's many factors that can cause high humidity under that floor. But most of that moisture can be ventilated out. That new floor boards sealed whole floor and it lost one of the ways to ventilate. Its the same like you change old windows for a new one. Thats why he need to add some more underfloor vents for better air circulation.
@@jozefkrizansky8120 How can you say it could be a leak when you were certain it was definitely ventilation.
Ventilating wont fix a leak.
Firstly I think itâs great that youâre helping people out like this and as you said in the video because no oneâs trying to sell a product thereâs just honest advice and help going on brilliant !
Secondly I think youâre right to ask whatâs changed recently to start this off?
the things you mentioned in the video are the extensions and the plumbing work
With the ventilation through the concrete subfloor in the extensions if thereâs not enough cross sectional area of ducting versus the many air bricks on the other original side the air flow may slow and as the warm moist air comes through and hits that cold north wall it will dump the moisture inside.
Also the recent plumbing might be leaking
Also that front driveway looks new and it might be draining onto the compressed clay layer and tracking across under the house
Cheers and apologies if someoneâs already said similar thereâs loads of comments !
I would check the air bricks havent been sealed up or possible add a couple more !!
I have a solid wall 1906 build, and I was impressed how dry it was underneath the floorboards and brick cavity. It's a similar contruct to this property. The only difference is that the front of my property drops at least 6 to 8 bricks below the vents to the ground level.
Judging by the fact there's a lot of efflorescence developing on those bricks, The water table must unusually high and moisture is wicking up through those bricks, suggesting good evaporation and airflow before it condenses back on the joists. Other than possible drainage/ pipe leaks, I wonder if there's a substantial tree, or long hedge nearby that's been cut down? Or a nearby construction to a neighbouring property leading to a change in the water table due to a new soakaway, etc?
I have had an issue myself many years ago with a detached waste pipe under the floor Fortunately I found it good time before more serious issues developed and its worth looking at water supply pipes that might run under floors in this age of property's. A small leak over a very long time can do and cause big issues.
I would suggest poor ventilation from the rear of house to front and paint on the outer brickwork preventing the moisture evaporating, allowing it to creep up the wall. There may be a leaking drain somewhere? The lower the floor is on the inner (under the floorboards) and the outer of house the less likely the damp is likely to show up inside, as long as the ventilation is correct. Old houses were built with gaps in the floorboards with plenty of ventilation and even the old working fires would draw the the moist air away.
Maybe the ground moisture is higher in your plot than the normal for some reason?
Usually you see droplets like those condensing under a roof; warm moist air condensing on a cold surface. I think it's condensation from the room itself. Warm moist air flowing to the under floor through the massive gap that's there since the crescent radiator was removed.
When I saw this or something similar it was under the floor flooding. There were heating pipes draping in to the water causing the water to evaporate very quickly which was making it extremely humid under the floor. It was condensating on everything including the wooden floor and joists. The flooding was due to garden works that had somehow not allowed the garden to drain properly other than to under the house.
Could well be his nice SOLID Hardwood floor wouldn't help, as formally there would have been tongued and Grooved softwood Timbers nailed down over the Joists, which in their own way allowed for some degree of leakage of air up through same helping with Convection, where as when the new hard wood flooring was fitted there might have been a Ply substrate and membrane put down when that nice Flooring was fitted over same also as you pointed out Paint Work around the bay could also be a problem especially if it's a Matt Gloss restricting the drying out of the brick work...coupled with the Clay earth on site, again your correct now that the trench has exposed the bay area One can now see how see how the subsurface conditions are behaving... most important in those old houses is the Down pipe Gulley's and Traps at ground level coming off the Roof and how the traps are working along with the likes of underground pipes taking that water securely away from the property...whether they go into the Main Drain or to a Soak Away otherwise the volume of collected roof water if not properly disposed of, will also add to saturate the surrounding properties soil ...which already could have been at a tipping point. Great Upload Rodger...
Itâs a really interesting one! Undoubtedly someone somewhere in the history of the house did something without thinking about it properly. Always the way - old houses, built well for the standards of the time, then when modernised, end up messed up. đą I think personally itâs a serious problem and will need a serious answer, Iâd start by taking out that floor so I can see properly whatâs going onâŠ
I think being north facing and the vent to the side it's not getting enough draw, originally the south side would have heated up and drawn air through the void.
I look forward to the follow up on this. My guess is excessive water under the house. Leaky pipe or drain. I would also suggest increase the under floor ventilation as there seems to be some history of moisture. Ideas to increase ventilation. Airbrick into another chimney if available. Add spinning chimney cowl to a unused chimney to pull the air up this will massively increase the cross ventilation under the floor. Cut a hole under the stairs and put a soil stack pipe in to sub floor area and then to the outside world creating and artificial chiney.
Thought similar. I thought maybe a couple of stack pipes at the other side of the house venting to high level to encourage passive through ventilation. Of course if the house is in a area where radon is an issue then a active radon ventilation system installed at the other end of the building would do the same thing but have a running cost. That's a lost of water under there though so it may be a symptom of another problem.
Blocked sokeaway backing up had the same with a 1955 bungalow, at first thought it was water main leaking
Lidle has inspection cameras on offer at the moment, might be useful for this chap
The external paint, the vinyl floor and the rear vents missing are trapping the moisture, clean out the external air vents and put some floor vents in
Floor vent to let the moisture into the room?
@@SkillBuilder the main moisture release would only be temporary for drying out controlled by windows and rear doors then it would equalise, all assuming there isn't a leaking pipe under there somewhere, lots of possible problems as you say, further inspection needed really
My airbricks looked clear on the outside, Iâve recently taken a skirting board off only to notice that the vent was filled in with expanding foam, I have since gone around poking all of them from the outside and everyone was blocked, we are currently suffering from condensation and high humidity and mould but luckily the walls are bone dry behind the wallpaper. I am stripping them off, then adding PIR, also unblocked all the vents, the humidity is coming down slowly
I also forgot to say once you get the condensation on the underfloor and joists under control it would be beneficial insulating the underside of the timber floor. Anywhere a cold surface meets a warm surface there is potential for condensation to form. My other observation is that from the limited view we have your sleeper walls do not seem to have sufficient openings in them for proper crossflow of air. It appears that the crossflow area is limited to the depth of the joist with the exception of a few minor openings which I would consider insufficient.
As you say it has a slate DPC and research has shown that these do not fail. Think the first thing I would do is check whether or not the RH is persistent above 60% (both in the room and floor void) as condensation might be at least a contributing factor and the base of the wall could be at dew point during the colder parts of the year. Following that, as you suggest, the existing under-floor ventilators should be checked and new vents added if these do not ensure through-ventilation is being achieved. If this is a cavity wall it would also be prudent to check the cavity is clear at the base. Given the degree of damp it would also be wise to check any services which pass near this area and in particular the position and condition of the water main and drains. I presume the rainwater goods are all in good working order as splash-back from the ground is often an issue particularly where ground levels are too high as appears to be the case here. This type of damp may well have a number of interacting causes therefore you have to un-pick these and quite rightly ventilation is one of the first things to check. Very difficult to apprise this sort of thing without seeing it first hand of course.
I've had similar build up of moisture where I stored my wood outdoors, and covered it with tarpaulin cover. But I've not allowed air through. The cover formed a convex shape, and was ground level around the periphery. The wood pile was about a meter and a half high. One day I got in for some wood for a project, only to find out it looked like in a cave, with droplets of water hangign from underneath the tarpoulin cover. There was obviously no water leak - no pipes in my wood storage. It's just lack of air flow. Simple as.... The dificult part is, how to create one.
So check the airbricks are not blocked - I'm currently rebuilind a floor in my toilet, and that air brick had no chance... Full of rubble!
Draw a floor plan, and mark all location of air bricks. Draw a straight line between all of them. Ideally, it would cover most of the floor. But if you have air bricks front of the house, and on a side, that would form a triangle, and it would cover only haft the floor.
If you can't figure out how to promote natural air flow, you might have to help it with a fan. I was prepared to buy myself one. Google "MORI WMF Sub-floor Ventilator" - appeared quiet, and didn't need much electricity to run. Servicable from outside. You would put that on the right side of the house, far end in the corner. Then have a PVC pipe spanning from there, left to right, with loads of holes in it along the length. Set the fan on pull, and it should draw air through the front bricks. The air should travel front to back, and cover the whole footprint.
Good luck
Is the paint on the outside wall breathable? Having air to the space under floors is one thing, but the bricks themselves have to breathe to the air directly. Bricks will absorb and release moisture overtime and with the seasons across the whole wall, and some of it will make its way downwards through the wall sitting at the bottom. If you fully seal one side of a wall, then it'll still to want to breathe and so will drive the moisture to the inside surfaces where moisture isnt being blocked from getting to the air.
Similar sorts of reasons why you get plaster which is damp on the lower sections of exterior walls, because the misconception is that by sealing the outside completely ( like with impervious cement render ) down to the ground thinking it'll stop rain soaking in, it actually stops the moisture getting out, and instead drives it inwards into the inside, soaking the plaster and inner wall and ruining the plaster.
As roger says you have a subfloor ventilation issue. The cross flow has been restricted when the extension built. You need to measure the relative humidity and temperature in the room and under the floor. Measure the temperature of the bay wall thatâs wet and youâll probably find the reduced temp around the air brick apertures is below dew point and the moisture laden air is condensing on the cooler surfaceâŠdo you have humidistat controlled extractors in the kitchen/bathroom to automatically extract moisture created before It becomes an issue?? Does the issue abate in the summer months? Sometimes to many airbricks reduce the temp causing this type of problem on adjacent wall finishes.good luck anywayâŠ.
PIV is your answer. Get a dri master loft fan or flat master. Simple fan that pressurises the house with fresh air, air will then be encouraged to flow out of gaps in the house e.g floors etc and this will massively help with the damp problem under the floors. Did this in my house and has resolved the problem.
Thatâs interesting. I think itâs a good idea here, for sure, given the impending wet rot diagnosed by Rodger. It strikes me a bit like treating the symptom of a problem though. Like a human being cooled down in an ice bath to âtreatâ a fever caused by a curable infection. That sort of approach might lead to a house in a palliative care condition in a few years time.
@@dwalsh3469 ventilation is key, if you can remove the moisture with fresh dry air from within the house then it will massively help.
@@richardc1983 I totally agree. Iâd still try and figure out the source of the damp though.
Not enough airbricks below the floor level⊠concrete floors on rear and left side of the property ⊠need some telescopic air vent to front and right flank⊠existing vents may be blocked by cavity wall insulation⊠or worse case new concrete floor
To have this much condensate under the suspended timber floor, it's highly likely that there are a number of issues that are all acting together. Firstly, the floor level externally looks too high. I'd dig a French drain externally in the affected areas. In addition, the air bricks are most likely blocked & need cleaning out. The floor needs to be lifted for sure, as it's likely that there's either a leak somewhere, a spring has found it's way out under there, or the ground water pressure is pushing up under there. Once the source of the water is found & resolved, adequate ventilation should be fine, but the source of the water needs to be found ASAP.
Get that floor up. Look what's going on & sort it ASAP. Your floor will not last too long with that amount of condensation & moisture.
Whilst hes sorting out the ventilation maybe installing a large fan piped to blow through the underfloor and get a good through draft going and help dry it out.
Either condensation or thereâs a pipe leaking under the floor. Iâd possibly look at the air bricks and remove them. Iâve seen people block them with insulation on the inside to try and reduce drafts. Never ends well.
Stick a coathanger wire through the air brick to see if it goes straight through, or is it a dead end against something? good ventilation I think is the problem itâs not being able to move the air through.
One other thing is to perhaps some flash ventilation in the floor in brass as this wouldnât affect the appearance of the floor, but give you extra ventilation
Why did it work for years and then stop?
@@SkillBuilder that problem maybe was there, but was not visible. As he mentioned in video there was radiator in bay. And maybe that radiator was helping wall to dry quicker.
We had this with terraced houseS up in snaefell Road tuebrook Liverpool. When it rained we'd get a layer of water on the clay that would then wick up the brick pillers and rot the joists. We never did fix the problem. He dug a ditch around the house wall, filled it with gravel, put under floor insulation, had lime plaster but never did stop it. We asked up the street and numerous properties had to have joists replaced.
Iâm thinking that the lack of air flow has existed for a long time BUT the stuck down vinyl floor has made it worse because now no moisture can pass through the floor at all. I would either core a hole and fit 4â pipe maybe 1.5m into the rear of the room under the floor and chimney effect like you suggested, or rip the lot out and replace with highly insulated concrete floor. That room must be cold at present.
Condensation.
Painted wall.
Walls not breathing.
Old hearths Straight on to ground.
Strip out floor.
Ventilate.
Insulate floor.
Studded membrane to walls
Insulate plaster board.
Job done.
And what if that is not the problem? You have wasted all the customers money on a red herring? We need to know the cause before we act.
Put in additional air bricks and lower the external ground level. Classic lack of ventilation.
It looks like condensation with a cold surface touching a warm floor, I would assume (could be wrong) there is no thermal insulate between the new floor boards and the old wood floor which has stopped breathing through all the gaps in the old floorboards. I would for the time being use a his dehumidifier with a makeshift hose and pull the moist air out.
Has there been a new housing estate built near you that has messed with the water table causing extra build up of water in the surrounding ground? This happened in an area of our town causing water based problems in many properties around that particular area. It badly affected the natural drainage in the vicinity. It turned out to be so called underground water courses which were inadvertantly blocked and diverted that caused the problems.
That amount of water points to a leak. It must be recent because that timber would be mincemeat by now otherwise.
I agree, it is an event that has happened recently
Might be misunderstanding this but the recent event was having the rad moved . Could there be some older pipe work that hasnât been capped . I know central heating is a closed system just a thought. Or when the new rad was installed did the Plummer drain the system into the void .Being clay the water would have nowhere to go
Water main, spring, drive gradient⊠Iâd drill a hole below the dpc & get a camera in there. Thermography after/while itâs raining can help determine.
POV Not 'dry rot' but just rot. Dry rot happens when boats are left in a dry dock and wood perishes and shrinks.
Also the air bricks look to the same face = no through movement. Back pressure stops the flow so needs a flow through. Its a pocket of cold bridging. All ground moisture is working 'wicking' into the thirsty common brick inside where its warm.
If sun hits that elevation, a trench with high vapour permeable substrate beneath the top soil, will encourage the moisture out of the bay. The external black paint also needs to be vapour permeable. Its goid its black because we know black gets warmer faster from sunlight... so what is the likelihood the bay structure is slowly heating the subsoil, like a wick in an oil lamp draws its fuel up.
My first house in Reading had so much water under the floor the whole floor was full of wet and dry rot so was replaced but to prevent it coming back I dug a French drain around the bay exactly as shown in the video but about 80cm deep , put a gutter set in concrete at the bottom and a pipe to take the water to the back of the house. Problem solved. In the case of your video I would take up a section of the floor in the bay by neatly cutting the oak floor and then the boards so the whole section can be lifted for proper examination so where the water is coming from. I thought the problem had come from when the garden was tarmaced
I wonder is it an old lead main thatâs sprung a leak under the suspended floor. Because that seems to be a case of hot floor meeting cold moist air (very moist air at that) not a normal amount of moisture for clay.
đđ just as Iâm writing this thatâs what youâve just said at the end đđ
My thoughts too. Iâve had an old lead pipe leak. Is property on a water meter? Easy to check for leak
We bought a property 8 years ago and we were aware of a damp problem in a front north facing room with a bay window similar to this. We took the property on and gutted the front room completely back to bare wall and all joists and floorboards removed. I was astounded one day when we had some heavy rain to find that water had percolated though the underlying clay and started to surface and pool in the bay window area. This subsided after the rain had gone but did it again when we had further showers. A bit of water i could understand but to have a not insignificant pool was way beyond my expectations. Ended up using a plastic DPM over the exposed soil and bricks/cement to hold it down. This helped, room once renovated hasnt had the same musty damp smell or any sign of damp at all in the last 7 years. I guess water just has to find a way sometimes! One other point, the previous owner had seen fit to put a garden bed in front of the bay window that covered all ventilation bricks! Once i had sorted this out ventilation bricks were present all around the bay itself as well as surrounding walls. This gives all round ventilation, which now uncovered, has better flow and is having the desired effect.
I'm a Surveyor, for my sins! - I've not seen that much moisture to the underside of the floor even with minimal air bricks with no cross-flow ventilation. To me it would suggest that there is another source of moisture. Given that microbore pipework was removed which can be problematic could there be any pipework insitu within the floor void that is leaking?
This can be exacerbated if you have clay soils and a high water table.
He says there is no pressure drop on the heating system
@@SkillBuilder it could have been a very slow leak that over time has caused ponding water in this location. Removing the radiator and pipework could have flooded the sub floor hence why it appears to be a recent event. I know the video was limited but the moisture did appear to be closer to the front, i.e where the radiator was. Clay soils will hold the moisture. Like you say there may be another source of water penertation; gound or otherwise, but given that the french drain detail is dry, leaking pipework over a long time with a sudden influx of water and clay soil would be my first guess
7:00 Cut a hatch in the side of the house below floor level. From there you'll be able to crawl and around and see exactly wtf is going on, and probably fix it now you have access. Anything short of that is just making (although some really good) guesses.
We had a similar issue on a similar house on clay. The clay is very wet due to high water table. Problem solved by adding extra air bricks (doesnât look necessary in this case if they are all functioning) and adding a plastic sheet over the ground and weighting it down with gravel. Lovely and dry down there now.
I would cut a hole for a hatch under the sofa. Find the joists and use a track saw. Add a picture frame over the perimeter in chamfered oak and it would look like it was meant to be there.
... I recently had a similar sort of issue with a property I maintain . Dug out a French drain all round the affected side , installed a soil drainage pipe into the trench , connected to drainage covered with pea shingle ... Re underfloor inspection , I have a couple of HD video camera probes for this kind of thing . Would be good to look through the vents and see what's going on . Probe cameras can be obtained reasonably cheap these days and are so useful for all kinds of things đ ...
This problem with the amount of moisture directly under the floor on the floorboards and joists could only suggest this is a recent event otherwise it would all be rotten. How long has the fireplace hearth been damp as well would suggest more issues.
I think something must be leaking through and will require more investigation via camera work or taking bricks out to try and see where the problem is before taking the floor up unfortunately I think this is more than just airflow.Roger please keep an update on progress as this is very interesting thanks
If I was this fella I'd get a fan in front of one of those airbricks, it would help dry out and may help trace the airflow through to the other ventilation.
I had a similar problem to solve myself, it turned out water was entering through the air vents.
The vents do look very low! The black paint wonât help either as itâs plastic and not allowing the bricks to breathe.
I think his mate was spot-on suggesting installing drainage..
I think over the years the garden and driveway have been altered and raised the ground level. I used to live in a old house with a cast iron boot scraper built into the wall outside the front door but the council must have paved over the original paving stones rather than dig the old ones up and the boot scraper was level with the pavement so i would guess the original ground level was 6 inches lower when the house was built.
Floor is old, but not yet rotted, suggests that moisture problem is fairly new. Unless extention is "new" 5 years ish I'd guess, then you have a leak some place that is allowing moisture build up. may only be a small perforation(s) causing constant, but tiny amounts of water ingress. moisture would build up on clay soil, Could be a pipe or possibly the chinmey as it's also damp near the fire place
He explained that the fireplace was original but had been extended forward and that section was also damp. In conjunction with other points mentioned, if the extended section has brickwork that goes down to the base without a damp course then it could be adding to the problem (but I doubt it could add that much water).
Front is shaded, won't dry out as much as its shaded. Lack of ventilation. The linoleum flooring is to cover up the damp problem. Possibly mold spores on sub floor??
Introduce more ventilation, possibly forced air by mechanical fans. French drain around the perimeter of the walls? Is there run off water from a neighbouring property causing extra dampness to your property? Moisture cannot escape from the floor covering. Salt/efflorescence is present on the bay window internal brickwork. Also you will get condensation from the warm air meeting the cold subfloor air at the point of the bay window.
You're right rodger You can have airbricks but unless they're arranged in such a way that they create cross flow ventilation they'll be limited in their use. They should be opposite each other.
Temporary fix for more ventilation - cut nice circular hole in floor where wood burner is - and a pipe to vent from underside floor into chimney stack. Metal pipe say 3â diameter - through sealing plate in the stack. The pressure fluctuations from chimney & ground floor should be very good!
Remembering end of vid - saying this is a recent event - wonder whether installing wood burner has changed the dynamics too - ie if chimney stack has been sealed when it mightâve been free before - thereby the room moisture / temp ventilated by a more open stack. Oh! Donât forget to look / see if room has vents at higher level in the room too! Any hot air / moisture will travel to the colder walls / room.
The internal part of the bay wall needs repair - maintain solid wall thickness as the insulation capabilities of the wall is severely reduced.
Insulate that wall on the inside. Itâs what Iâve had to do in the coldest room - north facing. I also increased ventilation at higher levels by simply drilling a series of 25mm diameter holes in brickwork forming an air brick.
My temp suggestion - just keep a check on condensation to the outside of pipe to internal area - may need to insulate
Just a thought but seeing the driveway covered in pebbles often it will have a dark sheet underneath to prevent weeds springing through could be worth checking that itâs a breathable sheet if itâs not the water from the entire drive way could be staying on top of it and draining towards the house
He could also put an air intake for the stove from under the floor run it from the centre of the house. That would create the chimney effect when the fire is not lit, and when it is burning it would be really powerful suction.
I'd be tempted to dig a French drain round the outside to reduce the moisture in the soil underneath.
I think the floor inside is completely trapping any moisture and therefore has exacerbated a pre-existing problem that more than likely occurred because of poor cross underfloor ventilation. Who knows whats going on under and between the joists. Iâd say they need to bite the bullet and take a section of the floor up maybe free up some throughflow/airflow space and possibly fit some telescopic vents. Theyâll be chasing their tails until they do this. I hope they get it sorted before it gets too serious! Keep us posted!
Suspended floors are great for insulation and warmth, but when they go wrong its usually a major job.
I'm replacing mine with solid as I go round with the extension.
i think by the looks of things in other comments and from what you said at the end roger, the source sounds like something coming up from ground level rather than the building being an issue as such. my guess would be if the cold main was lead and has split somewhere under the house, seen that before where they're just laid in the dirt, especially in clay and with the last 2 or 3 years with those very dry periods there's most likely been more ground movement than before
I'm an ex Pat Brit been here in Canada for 45 years, started my building career in the UK so I remember the methods used back in the day.
Here we either build on a concrete foundation with a crawl space at least, or a basement, so under floor issues like this one are uncommon. But saying that we cannot build a crawl space now without a poured concrete floor with vapor barrier underneath to prevent moisture.
Looking at this situation I think a ground water issue is the cause, and it doesn't look like there is any perimeter drainage where he dug down outside.
I would try putting one around the front of the house, obviously draining away, cheap try, before you have to rip up the entire floor to see if it is a plumbing issue, and somehow get a moisture barrier down.
I think drainage is the most important feature when building from scratch, and when this house was built it didn't really exist.
Ok, so im just a lowly handman.
But i recently had a customer with damp interior walls around the windows.
1950's cavity red brick construction.
Had new double glazed units 10 years ago.
The window fitters had stuffed a load of what looked like loft insulation into the cavities around the window enclosure.
It was seriosely wet!
This insulation was wicking moisture either from the external wall or the ground to the internal brickwork.
This looks like a similar construction with newer double glazed units, and even has the same airbricks.
Worth looking into the cavity to see if the window area has been filled with expanding foam or wool type insulationđ€·đ»
Fit air brick centre of bay one brick up from doc remove some bricks and clean out cavity below doc and refit the additional air brick allow air circulation in the cavity on the curve of the bay
For me, Iâd start by making a floor plan of the house and marking the solid floor areas and suspended floor areas. Then mark out the air bricks and make sure there are no obstructions under the floor blocking the airflow. Iâd drill some discrete holes in the floor and look beneath the surface with a boroscope to gain a good understanding of the scale of the problem and then finally if itâs necessary, add a small ventilation fan to one of the air bricks to help that ventilation.
blast that paint off on the front then either lime render the bow wall as a feature or just leave the bricks as they are to see what happens ---- both cheapest ways to find the problem.
PS--- please tell me you ve checked the sides of window to see if it is sealed properly?
What about the panted brick? I had a mirnor damp problem on my Victorian house which is actually South facing but shaded by tall buildings. I couldn't work out why this was but the engineering brick had been painted - I used paint stripper to remove it and it cured the problem. The bricks can't breathe and the moisture had nowhere to go because the airbrick was not sufficient for a house that was designed to be brick, not painted brick. The back of the house has solid concrete floor so similar lack of ventlation, but removing the paint has cured it believe it or not.
possible sleeper walls blocking air flow...ive had to punch out a few lower bricks before because the builders of the house bricked up between the the floor joists right up to the underside of the floor boards...which in turn if theres no dpc on top of sleeper walls this will transfere moisture from the oversite...
Yep. Possible water leak. If you have a meter out in the road. Turn off all the taps , check they are not dripping, check any loft tanks are not filling etc and look to see. If meter is spinning.
1930s houses were mostly plumbed with lead mains.
Is that bay just a 4 inch wall ? north facing it will be like a fridge and a massive cold spot , ripe for condensation.
Never liked concrete floors in on old houses, stick to timber is my preference.
Yes. Brilliant
Cut a square out of the centre of the room floor & have a good look around. I say the centre, because the repair can be hidden by a rug afterwards.
You should be able to identify the cause from there & perhaps fix it from there. If not, then take up the whole floor. I'm guessing the damp is rising through the floor cavity for reasons unknown at the moment.
Take the airbricks out and see if they are even venting the subfloor. Many times they are just venting the cavity or are blocked. Cheapest first option.
It is likely you have several problems , obviously historical damp/condensation problems but also something has changed recently, that condensation under the floorboards is max a couple of months old - my guess is you have a slow leak from the new plumbing
I'd say that when the extension was built it blocked the rear aspect air bricks up. T this would explain the apparent historical attempts at remedying the situation. Now the owner says the front of the house is quite sheltered, to my mind this will exacerbate the problem. In fact I'd go as far as to say even just one point of ventilation front and one back would be more effective than what is presently there. I had a condensation issue in a loft once. One year I went up to get the decorations on a cold, still evening and felt a drip, upon looking up the felt and timbers were wet in water. So I simply had a vent tile put in on each side of the gabled roof, and to my releif it cured it. If you can't feel a slight draught in a void, be it a roof or underfloor, then something is wrong. This is because there is nothing to carry away any moisture, that was a modern house, our first victorian terrace had a virtual hurricane blowing through and was as dry as a bone! Of course I'm only a DIY person at best lol others more knowledge may tell me if I'm wrong. Merry Christmas all. đ
Just to be sure I would poke through air bricks with a length of coat hanger wire just to make sure that the inner skin of brick is open right through to under the floor. If the house has been cavity wall insulated it is important to check that the air brick connection between inner and outer courses have not become blocked. There is n9 way with an intact damp proof course and a five air bricks for the level of damp as shown to exist. Digging out a deep French drain around the wall is good idea. When it is all dry spray the under side of the floor and joist ends with 5 star wood treatment.
Pressure test your water main and possibly your neighbour (s) cctv any waste water or rainwater. See drainage drawings. High water table with fluctuating levels then send samples away for analysis(rain or freshwater source will confirm what your looking for) . Thermal bridging through wall yes but not causing that level of moisture. You need more cross ventilation and it looks like the sleeper walls are not nearly ventilated nearly enough. Knock a few bricks out to increase airflow. Double up on air vents in solid wall. Easy to fit. Central heating leak if attached to F and E tank but you mention pressure gauge so unlikely to have that.
The mains pipe could be burst under there pissing so much water the air canât get rid of the moisture
mains water leak ???
Seems like a broken drain to me or leaking water main into the house, I have worked on loads of Victorian houses in London and a lot had drains running through the middle of the house, we used to dig them up and re route them around the sides as many were cracked
This is warm air in the house moisture rich condensing on the cold parts of the house.. seal all the holes. Job done.
Clay subsoil (poor natural drainage) and oversize level below floor appears lower than external ground level therefore probably retaining quite a bit of ground moisture and based on the amount of condensation on the underside of that floor the cross flow ventilation is definitely impeded for one reason or another (blocked/removed during previous work) the sleeper walls appeared to be 'honeycomb' to allow air through, but if the vents to air have been blocked then its irrelevan. Cross flow ventilation is key, vents on adjacent walls (front/side) is not enough. If reinstating the cross ventilation is not possible then maybe replace with a solid floor is the only solution đ
something is adding moisture under the house.
possibly a broken pipe leading from a bathroom basin or something. every time it is run, it dumps a bit more water under there.
possibly leaking water main.
possibly just the clay causing it to pool under the house from the surrounding yard.
possibly rain draining down through some bad roofing material, down the brick wall, into the foundation area.
no matter what, the best option is to explore under the house.
it is also not helped by the laminate floor that blocks all flow of moisture. though, that might just cause the whole house to be humid. maybe the previous owner used the lamiante floor to hide the moisture problem ;)
Hi Rodger, from a joiners prospective Iâd be concerned about cold bridging from the warm room to the cold underside of the floor. The flooring Being only about 28mm with no insulation and having the wood burner and the new working radiator itâs a lot of heat on the surface and a very cold underfloor space (specially in winter), also the more air bricks the more moisture that can be brought in from the outside, hope this helps.
Best of luck
I think this is lack of underfloor ventilation. I know of neighbours who black off the air bricks during winter and they get a lot of damp forming until they open them again in spring. The reason why they block them during winter is because of the cold wind blowing under the floor space making the house cold. More ventilation needed. I think he will need to get under the floor or a micro camera through the air brick to see what's going on as some of the air bricks may have become blocked.
The other thought is cold air hitting the warmer floor above. Maybe lack of insulation on the floor.
Or leaking pipe running under the house.
I'd have the drains checked, and the incoming water main, that's a lot of moisture under the floor,
If it is just down to ventilation then a fan could be fitted to one of the air bricks to ensure good air movement. And a land drain around the building would be a good idea in any case.
A decent joiner should be able to cut a removable inspection hatch in that floor and use the piece removed as a hatch.
Hello Roger
Start simple clean air bricks and make sure the pipes to air bricks are clear.
Check cross ventilation
Check for leaking pipes/drains etc
Also just a wild guess but has anybody checked the water table? Is there a stream or is the garden a bit water logged or running up from the house.
First thing check the air bricks aren't blocked. Then check for a high water table. Dig a pit outside several feet deep and see it fills with water. If it's a very high water table then that ventilation may not be enough so you might need another airbrick introducing to create better cross flow. Another source of the damp could be a leaking water feed or a broken drain either under the floor or just outside, so check the route of all your pipes.
Hi im not a damp expert but I have been working in construction since I left school and my personal opinion is that if you are using the stove burner regularly then that is more than likely the source of your problem. Basically the bottom of the stove is also getting hot and the heat is being distributed underneath the house then the hot air is meeting the cold air and creating moisture 100%.if that doesn't solve the problem then I personally would just pump concrete under the building.
The underside of my wood burner hardly gets hotter than 50 deg due to the convection current bringing cool air in at the bottom.
my bay was the same and with the house being changed or added too any damp that started was in that bay area, add an air brick to the outside of the bay it will create a point of air all around the bay area.
You mention that some recent change may have caused this issue. A contributing factor may be the painting of the plaster with emulsion paint. I have worked on old buildings which have lime plaster over painted with emulsion paint, in many cases this has trapped moisture in the masonry which would have evaporated inside . Frequently one can see blisters forming and the plaster becoming detached. Though this is not the full answer to the problem it may well be a contributing factor.
Cliff T
I agree thats new moisture,although there may have been some before but not enough to notice. I think theres good airflow.( i thought the vents were a course to high at first!) I wonder if work have been done to the back garden, walls, different levels that has changed a natural watercourse...Too much moisture under there, it could be running down a vent pipe from the back extention!
Boiler might not be losing pressure and leaking but check where the water main and the supply pipes run for the taps and toilets. Only takes a small hidden bit of damage and that could leak enough without being seen.
cracked drain pipe, leaking water mains pipe is where I would be looking to eliminate the problem first.
Is the old microbore piping leaking? Maybe that's why the radiator wasn't working. Was he losing boiler pressure?
Maybe his soakaway has a problem.