linear (ACO) drainage to patio

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Hello all.

After 5 years (!) of saving for a deposit, my wife and I have just moved into our first home, a 200 yr old cottage which is in need of some TLC.

The first job was to try to sort a bit of damp we have on the inside of the back wall of the house. My initial thought was to drop the level of the back yard, which was quite high, almost up to floor level, and with no DPC.

After spending 3 days smashing up the old patio and sub-base, dropping the ground level by 100mm and carting over 150 bags of rubble to the tip in my car, I bought a load of slate flags and asked a builder to come and lay them. I wanted an ACO drain across the back wall of the house as extra damp protection, so the builder suggested we might as well just slope the patio TOWARDS the house since the water would run off into the ACO drain. This didnt sit too well with me but the logic seems fair enough, but the problem is that the ACO drain doesn't run the full length of the back wall! The builder couldn't figure out how to join in an extra bit of of ACO in the area behind the soil pipe (see photo) as the soil pipe is really in the way, so he just cemented that area in. No big problem so far, but when he put in the long length of ACO, it is sitting too high, about 5mm higher than the flags! Rain water on the patio now runs down towards the house, hits the edge of the ACO drain, and then runs sideways until it pools in the cemented area. This is EXACTLY the area where we have damp on the inside of the house, so what we've ended up with is a patio which very effectively channels water to the exact area we were trying to protect!

I am planning on remedying this situation as we have lost faith in the builder's understanding of the problem (there are other problems with the patio too which I won't go into).

We are going to drop the level of the long run of ACO so that it drains properly, but i'm still not sure how to patch in a bit more ACO in that damp corner as it is effectively blocked off by the soil pipe. Does anyone have any bright ideas on how I can get a bit of channel in there and figure out a way of draining it off into the main length of channel?

Sorry that was such an essay. As I said, this is our first home, and a lovely old house that was left to ruin and needs protecting. The first few months of home ownership has been a bit stressful and i'd be glad of anyone's advice.

Thanks! :D



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Whilst sometimes you have no choice but to fit an aco type drain and run the whole lot into it, (common one being a garage at the base of a sloped drive) it is a bad idea doing it next to a building i.e on a patio where the fall will not be as steep. You of course sometimes have to follow the lie of the land but even when running a patio toward the house the last flag should run away from the building if possible and then run the water into a drain or around one side of the building.

The bit behind the soil pipe can simply be a bit of benched mortar or concrete, as long as it runs away from the house that's fine.
 
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If you`ve got damp where the soilpipe is - you could have a broken drain pipe :idea: hire a borescope and look after taking off that access cover ;)
 
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hmm re-reading your post maybe lifting and relaying 2/3 flags next to the drain and putting a suitable fall on them would be worthwhile.
 
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Hi all

Thanks for the replies.

Neo, i'm interested in your comments about fall.

My question is, why is a patio with a very shallow fall worse than one with a steep fall?

My patio is slate and will have resin pointing. If there's a heavy downpour, the water should run down the patio towards the house and then into the ACO drain. If there's light rain, the water will probably just sit on the surface until it evaporates.

I'm guessing you a concerned that if the slope is not steep enough, water wont drain as fast and might sit, and gradually seep into the sublayers, and that if the slope is heading house-wards, the dampened earth would end up being closer to the house than if the slope was headed the other way (away from the house). Have I understood this correctly?

I really appreciate your comments, they're very helpful. Your answer will help me to determine what my next steps should be.
 
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No i didn't mean a small fall was preferable. I meant that most people like to sit on a patio at a table and unless you want your drinks to be at a crazy angle the patio needs to be relatively level. Something like 1:50 fall.

When working with shallow falls like this I think it is much better to lay the last slabs falling away from the house.

However when you have a steep slope such as a driveway running maybe 1:10 down towards a garage the water will rush down it at such a rate that even if you layed the last slab at the garage door with a fall away from the building the momentum of the water coming down the hill would push it against the wall anyway and so in this situation you need an aco type drain.

In short i would never run water against a building, even with an ACO drain, unless there was no other option because it is creating a potential problem that doesn't need to be there.

Does that make sense?
 
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Kind of...

I guess what i'm asking is, if there's an ACO drain in place, what is the potential problem with running the fall towards the house?

Or to put it another way, what is meant by your comment:

"When working with shallow falls like this I think it is much better to lay the last slabs falling away from the house".


I'm not arguing with you, just hoping you can explain how it could cause a risk to run it that way if there is a drain in place. Do you just mean that it's something that could go wrong that doesn't need to be risked? i.e: if the drain were to fail?

Cheers

:D
 
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Couple questions.
Has Aco got universal end cap next to soil pipe?
Assume Aco falls towards soil pipe?
If so, is there a vertical outlet connector piped to soak away?
To determine volume of water, what is size of patio.
Answer questions and will give some suggestions.
oldun
 
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Whilst sometimes you have no choice but to fit an aco type drain and run the whole lot into it, (common one being a garage at the base of a sloped drive) it is a bad idea doing it next to a building
And I thought that was the idea... But hey...
 
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Do you just mean that it's something that could go wrong that doesn't need to be risked? i.e: if the drain were to fail?

That pretty much hits the nail on the head. Linear drains are made and used to help solve a problem (i.e in front of a garage at the base of a slope) when no other solution will work. In a case like yours they are a last resort and certainly not a first choice when simply laying the slabs falling away from the building is less work and more fool-proof.
 
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Do you just mean that it's something that could go wrong that doesn't need to be risked? i.e: if the drain were to fail?

That pretty much hits the nail on the head. Linear drains are made and used to help solve a problem (i.e in front of a garage at the base of a slope) when no other solution will work. In a case like yours they are a last resort and certainly not a first choice when simply laying the slabs falling away from the building is less work and more fool-proof.

So when the slabs have to be laid uphill.... what do you do...

Hit the nail, or the head...
 
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the last flag should run away from the building if possible and then run the water into a drain or around one side of the building.

You then hit the unhelpful smart-arse over the head with the hammer.
 
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