dazmatic Posted February 9 Share Posted February 9 Hello everyone! Thanks for taking the time to have a read through - any productive help/advice is much appreciated. We've recently had a bunch of paving installed including a new pathway across the garden. It left an island of grass higher than the paving. Decided to dig out, haunch the paving, fill with type 1 and build a low level deck. Our current issue is water and drainage - see attached. To the right is the main paved area, to the left a short path and sloped grassy area to the left of that. Obviously, this isn't finished level yet, we've got more type 1 on order and will bring the level up significantly on the right side (where the main paved area is) and so during heavy rains, will displace most of the water you see here. It does drain, albeit very slowly especially considering how saturated the ground is currently. My question is, what inventive ideas do you have that I could do to improve it? The ground is firm so I'm not concerned about movement of the decking or subsidence and it is relatively shallow. A thought that occurred to me was where the path meets the pavement there is a wide joint, wide enough potentially for a short length of PEX to be stuffed down between this area and the grassy slope to provide a drain/run off - not the worst, nor best idea I'm sure, but I'm clutching at straws. TIA Link to comment Share on other sites More sharing options...
ProDave Posted February 9 Share Posted February 9 What is your plan? You say "decking" do you mean timber decking level with the paving? If so you don't need all that MOT1. Compacted MOT1 drains very poorly, you would have been far better infilling that with crushed gravel that would allow natural drainage. At the very least try digging out a bit of the MOT1 back down to soil and see if that drains. Link to comment Share on other sites More sharing options...
dazmatic Posted February 9 Author Share Posted February 9 (edited) So the plan is a timber decking, installed on risers, hence the type 1. It was originally meant to sit level, or just above the paving at least at the far/gate end, however given the drainage it's probably not advisable now. Because the paving at the gate end is higher than the main paved area, type 1 was/is being used to bring the level up at one end and provide a base for the risers. Edited February 9 by dazmatic Link to comment Share on other sites More sharing options...
Conor Posted February 9 Share Posted February 9 If you're building a timber deck, you need to allow a good 100mm underneath for ventilation, so you'll need to dig that out. Might be better off just paving it. Link to comment Share on other sites More sharing options...
JohnMo Posted February 9 Share Posted February 9 Remove type 1, replace with soil or sand, form the deck with 3 to 4" posts, post-crete into the ground. A lot to be said for SuDS. Lots of hard landscaping no use for rising water levels and residential run off into rivers. Link to comment Share on other sites More sharing options...
dazmatic Posted February 9 Author Share Posted February 9 I actually had more type 1 coming today - 2 bags. Just cancelled and lost 20%, but I guess the devil you know etc. The reason I didn't do posts is because the ground is made up, well compacted and full of stones/rubble/concrete etc and given my back and I'm on my own doing this, a nightmare to dig. It was extreme work just to get the level down to where it is now! Happy to remove existing type 1, not too much of a loss. Link to comment Share on other sites More sharing options...
dazmatic Posted February 9 Author Share Posted February 9 So, I've been giving this some thought this afternoon. The right side of that picture is the lowest point of that area, hence the pooling up. Would it be better if I installed a 'french' drain of sorts along that edge, run it under the paved pathway and into the sloped grassy area next to it? It wouldn't need to be particularly deep which saves me some digging and the slope and grassed area would allow it to run off. Link to comment Share on other sites More sharing options...
TonyT Posted February 9 Share Posted February 9 Dig hole, line with landscape fabric, fill with large stones, wrap stones up with fabric cover up. Link to comment Share on other sites More sharing options...
dazmatic Posted February 9 Author Share Posted February 9 1 hour ago, TonyT said: Dig hole, line with landscape fabric, fill with large stones, wrap stones up with fabric cover up. This is what I'm thinking - perhaps run it under pavement via pvc as a duct into the sloped garden as run off. OR alternatively, remove type 1, replace with crushed gravel up to required level, level with patio to right off picture then build on top. It'll displace most of the water but allow for drainage still. (I understand now that type 1 with a lot of fines prevents good drainage) Link to comment Share on other sites More sharing options...
twice round the block Posted February 9 Share Posted February 9 Remove Type 1, get Type 3 with specified with no fines and lay on a non woven geotextile base as this stops mud and fines coming up through the fabric but allows water to drain away 1 Link to comment Share on other sites More sharing options...
dazmatic Posted February 9 Author Share Posted February 9 6 hours ago, ProDave said: What is your plan? You say "decking" do you mean timber decking level with the paving? If so you don't need all that MOT1. Compacted MOT1 drains very poorly, you would have been far better infilling that with crushed gravel that would allow natural drainage. At the very least try digging out a bit of the MOT1 back down to soil and see if that drains. When you say crushed gravel, was there a particular material? I get lost in all the different aggregate names for the same things! Something like limestone chippings? Link to comment Share on other sites More sharing options...
ProDave Posted February 9 Share Posted February 9 3 hours ago, dazmatic said: When you say crushed gravel, was there a particular material? I get lost in all the different aggregate names for the same things! Something like limestone chippings? Crushed so they interlock together and are stable, as opposed to round gravel that is more prone to settling. Link to comment Share on other sites More sharing options...
dazmatic Posted February 15 Author Share Posted February 15 So I figured I'd provide a bit of an update. Type 1 is being removed and relocated. I have sourced some 35mm perforated pipe which can just sit in the lowest spot beside the paving on top of the existing geotextile and be buried under some compacted limestone chippings. The plan being to trench under the pathway to prevent disturbing it with 40mm PVC pipe and run the 35mm perforated through it and down into the sloped grassy area for 3-4m length. It'll at least prevent hopefully all the standing water and offer a chance to drain it off a bit quicker. Link to comment Share on other sites More sharing options...
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