Field drain for Retaining wall - installed the correct way - to last forever
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- čas přidán 28. 07. 2024
- How to add or build a field drain to a retaining wall? It’s sometimes called a French drain. We’re going to run it around the back of the wall,…. so on the ground side of it retaining wall, to relieve the ground pressure from the water by redistributing it further down the slope.
I’ll explain the fabrics and pipe you need, the dimensions to allow, what a burrito wrap is Abbas why it’s important to our drainage, gravel, hydrostatic pressure, soakaways and a whole load of other things. Non woven v woven fabrics and how to choose.
If you want to access the files, such as the pricing and materials document, you can go to the link below to download.
www.buildbetterthings.com/resources
And side note…a field drain also called a weeping tile, trench drain, filter drain, blind drain, rubble drain, rock drain, and French ditch.
See my video for how to dig out land and build a retaining wall in your garden
Dig ground & Retaining Wall for Timber Frame Extension
• Dig ground & Retaining...
0:00 Retaining wall problems with no field drain
1:14 Setting out the field drain - dimensions
2:00 Field drain - building materials and physics
3:50 Retaining wall and dig out for sloping garden
4:00 Field drain installation, gravel, perforated pipe
5:21 How to optimise drainage - maintaining percolation
5:50 The importance of non woven fabrics
7:50 Field drain spreadsheet for ordering and quantifying
8:32 When to use a woven membrane - Jak na to + styl
I am currently in the process of doing something very similar, for my Block built Workshop, which on 2 elevations is the supporting wall to a sandy/gravel bank at 1.2 metres in height. I am installing Hyload 2000SA Tanking Membrane and then to relieve the "Hydrostatic pressure" a Dimple matting, then 100 mm land drain as shown in your video, with 2 inspection/cleaning pits, same sock , but i have gone for 20 mm round smooth gravel as the fill but will top with smaller aggregate as I progress vertically. I am only a DIYer but it is reassuring that I appear to be doing it correctly, because I would have hell on in a few years, if water and mold appeared etc, a belt and braces approach is the cheaper option for the long term I think .... Thnx for the video, looking forward to the next !
I did not mention access / inspection points but I should have. It sounds like a great amount of research for your project you are doing. Thanks a lot for sharing.
Very helpful as always, thanks for taking the time and effort to share.
Brilliant video buddy
This is great - thank you. I'm planning on building a garden gym / home office, on a sloping site, using steel screw-piles and timber floor frame, with timber framed building on top. Presuming if I build a retaining wall like this, I can build the timber floor frame (supported by screw piles) within the inside of retaining wall to end up with a floor level nearly the same as with the floor level outside i the garden?
if I’m understanding you correctly, yes, I’ve done exactly that if you look at the videos of the micro home I built.
@build-better-things I have to figure out how to replace an existing 35 to 40 year old timber retaining wall. My confusion is with the French drain. The wall I'm tackling is basically U shaped (8 feet then a 90 degree turn and it goes for 16 feet then 90 degrees again for about 9 feet. My trouble is that both sides of the U (8 foot and 9 foot parts) where the timbers end are buried on both sides into a small hill. Basically the wall juts out from the hill and acts as a sort of look out point, so I'm not sure where the drainage pipe for the French drain could drain? Any thoughts would be very welcomed.
Hi There, thanks for the videos always appreciated.
I was hoping you could expand on a comment you made a few months ago regards a flat roof. You said you should only have timber based composite above the insulation as a last resort. And you should instead bond the EPDM onto the Insulation. Would that be insulation wrapped in a DPM?
Its just all the videos I've watched regards flat roof extensions and garden rooms have OSB above and below insulation, for a base for the membrane?
And would the same principles apply for other roof coverings on flat roofs?
Thanks in advance if you see this.
Yes, always bond EPDM directly onto insulation. It’s a terrible detail to have a timber deck above the insulation, especially one with lots of impermeable glues like osb or ply , and yet sadly one which is done all the time in the uk. think about how the dew point works and where it occurs on a flat roof. I don’t understand what you mean about DPM. that type of membrane would never be used within a roof.
What if you're hardscaping/paving the ground above the retained side of the wall (as for example, the wall is a boundary wall and the higher retained ground is on the side of your garden and you want to pave up to the wall)? Surely you can't have pea gravel as sub-base underneath paving, it's too unstable, no?
I wouldn’t ever use pea gravel for that. Did the vid suggest otherwise? I hope it didn’t. I would use membrane, then hardcore, then sand, whacked down, then my paving and jointing. But I’m not an expert in that…there are new technologies coming through
@@build-better-things yeah, no in the vid it's clearly for the sake of putting grass/earth on the top surface, so not the same. But, without knowing certainty, I'd worried if pea gravel was the only possible effective permeable aggregate to use within the drain ditch. I've done one last year and used 20mm limestone chippings and non woven material around the pipe, then left it and the clay ground alongside to settle in (plus budget and time constraints preventing full finish then). Aiming to finish over the top of the ditch in the next few months, topping off with 20mm across whole laying surface, compacting, then to graded compacted sub base of chippings to grano/type3 to dust for an even top surface across the whole area up to the wall. Hopefully, that will be stable while still allowing some permeability (laying travertine paving, so that's semi-permeable).
Where about u based?