Paving close to DPC / level thresholds?

[Roger440]

Well, chaps and chapesses, been a while since i was here, but i have a question,

 

The back wall of my house way clearly very wet upto the DPC. Investigation releaved that the patio had been laid with a slight fall to the wall, and being natural stone was layed on a bed of motar or similar. Nowhere for the water go, so end result unsurprising really. The patio was one brick below the DPC.

 

Having dug all this out, its starting to dry out nicely.

 

However, once the sewage treatment plant and rain water soakaway are installed, i need to re-instate a patio.

 

Obviously it needs to slope away from the house, but that really raises it up a touch. Dont reallywant to lower the whole patio, its big!

 

Traditionally, the paving was supposed to be "2 bricks below the DPC". Clearly the requirement for level thresholds means that cant be achieved Ive been looking at the various detail drawings for the thresholds, but whatever system is used, does the wall ABOVE the DPC not get wet? I thought the 2 brick idea was to counteract rain bouncing / splashing the wall?

 

Plenty of you guys must have level thresholds, so is you wall OK?

 

The wall inquestion is west facing, so gets all the weather.

 

Thoughts?

 

[Oz07]

Leave gravel trap between wall and patio, seal brickwork a few courses above dpc couple of options

[Redoctober]

Could you not fit a drainage channel which then runs into the main rainwater system? An example of which is here - https://www.drainage-channel.co.uk/

[Jeremy Harris]

We did exactly as @Oz07 suggests, works a treat.  We have a coarse gravel French drain all around the house, around 100mm wide to over 300m wide in places.   The section alongside the patio is around 100mm wide, and at the back door, where the paving comes right up to the door threshold level, we have an overhang on the stone of around 50mm, with coarse stone packed in the gap and the stone paving being about 5mm clear of the threshold.  This seems to work very well.

[lizzie]

Ive got a french drain and gravel topped with decorative slate.  In front of that I have a slot drain, that does the level threshold area where I not have gravel as I wanted my tile to run up to threshold.  Slot drain runs right around the patio perimeter

 

[Roger440]

10 minutes ago, Redoctober said:

Could you not fit a drainage channel which then runs into the main rainwater system? An example of which is here - https://www.drainage-channel.co.uk/

 

Indeed i can,or gravel as Jeremy suggests. Both make good sense. 

 

My main concern was splash soaking the wall? I guess with a widestip of gravel that this is less likely than hard paving. 

 

But no one has this problem? Maybe im over thinking it?

[Roger440]

2 minutes ago, lizzie said:

Ive got a french drain and gravel topped with decorative slate.  In front of that I have a slot drain, that does the level threshold area where I not have gravel as I wanted my tile to run up to threshold.  Slot drain runs right around the patio perimeter

 

 Thanks Lizzie. But as per my post above, does the bottom of your cladding not get soaked in heavy rain from the water splashing back onto it?

 

Looks very nice though

[lizzie]

3 minutes ago, Roger440 said:

 Thanks Lizzie. But as per my post above, does the bottom of your cladding not get soaked in heavy rain from the water splashing back onto it?

 

Looks very nice though

No the cladding is above the ground level by a few inches and it is set back behind the french drain, we have an aluminium trim around the eps then the cladding is above that.  

 

 

[Roger440]

2 minutes ago, lizzie said:

No the cladding is above the ground level by a few inches and it is set back behind the french drain, we have an aluminium trim around the eps then the cladding is above that.  

 

 

 

Ahhh, i see. There is EPS behind that trim. 

 

My issues is the bricks on my house are like a sponge. They just soak up water, hence my concern.

[Jeremy Harris]

We got around the water splash problem by fitting 200mm high black uPVC around the bottom of our cladding.  Seems to work well.  I didn't bother to do this for the garage cladding and as a consequence the bottom of the larch cladding on the garage is looking a bit manky.

[Oz07]

1 minute ago, Roger440 said:

 

Ahhh, i see. There is EPS behind that trim. 

 

My issues is the bricks on my house are like a sponge. They just soak up water, hence my concern.

Seal them then. Theres product you paint on the brickwork, dries clear

[Roger440]

15 minutes ago, Oz07 said:

Seal them then. Theres product you paint on the brickwork, dries clear

 

Sadly, that stuff is exceptional at holding moisture in as well. Having direct experience of it and seen the long term results,we definitely wont be doing that.  

[lizzie]

My garage is all brick no cladding.  We have the same french drain with gravel/slate as around the house that sits against the brick below dpc level.  In front of door we have an aco drain similar to the one suggested earlier by redocober, its a slope down to the garage so we need to stop water running in.  It works well no issues at all and we have a resin drive.  Sorry have not got a close up pic to hand.

[Roger440]

18 minutes ago, JSHarris said:

We got around the water splash problem by fitting 200mm high black uPVC around the bottom of our cladding.  Seems to work well.  I didn't bother to do this for the garage cladding and as a consequence the bottom of the larch cladding on the garage is looking a bit manky.

 

Which is exactly my concern. I cant put anything in front of it, as that would look weird.

 

[Roger440]

1 minute ago, lizzie said:

My garage is all brick no cladding.  We have the same french drain with gravel/slate as around the house that sits against the brick below dpc level.  In front of door we have an aco drain similar to the one suggested earlier by redocober, its a slope down to the garage so we need to stop water running in.  It works well no issues at all and we have a resin drive.  Sorry have not got a close up pic to hand.

 

Exceptional  

 

How old is it though. Looks brand spanking new?

[lizzie]

1 minute ago, Roger440 said:

 

Exceptional  

 

How old is it though. Looks brand spanking new?

It is brand new!  I think same principal would work work with old bricks though our french drain is about 70 wide which is enough to cope with any splashing.  Our bricks are not getting wet down there.

[Roger440]

2 minutes ago, lizzie said:

It is brand new!  I think same principal would work work with old bricks though our french drain is about 70 wide which is enough to cope with any splashing.  Our bricks are not getting wet down there.

 

You have a decent overhang there too, which will definitely help, but i hope your right. Will be really interesting to see it in a couple of years time.

 

My wall is the gable end, overhang is an inch at best, and west facing, so worst combination possible.

 

The pic below shows just how bad it got, though that laregly as a result of it puddling against the way, but the bricks are so soft it just wicks up the wall.

 

 

[lizzie]

You could try a slightly different approach.  I have a townhouse part of a Victorian school conversion.  Suspended timber floor and no modern damp course. Conservation officer was a tyrant with the developer on the build.....Munster joinery did the windows its on their web site.

 

To solve the problem of drainage/splashing around the walls which are porous old bricks they put in  a french drain but left it open. It is deep maybe a foot deep with just an inch or so of gravel in the bottom.  It is faced with slate on the inner side of the earth trench wall and slate against the brick side too to protect the old brick but still let it breathe.  This big trench takes all the water and it goes away and because it is so deep there is no splashing.  It was specificaly designed to prevent splashback against the walls. There is a shallow border for plants all around to make it safe from falling in and hide it a bit. There is no garden as such its all paved . At thresholds they essentially created a bridge, a sort of small culvert type thing so there was a level threshold with paving right up to the threshold and under it the french drain.

 

There is no problem at all with damp on the walls or drainage it works.

 

I cant find a close up but if you zoom in you may be able to see what I mean, Im not great at explaining it.

 

 

[Roger440]

41 minutes ago, lizzie said:

You could try a slightly different approach.  I have a townhouse part of a Victorian school conversion.  Suspended timber floor and no modern damp course. Conservation officer was a tyrant with the developer on the build.....Munster joinery did the windows its on their web site.

 

To solve the problem of drainage/splashing around the walls which are porous old bricks they put in  a french drain but left it open. It is deep maybe a foot deep with just an inch or so of gravel in the bottom.  It is faced with slate on the inner side of the earth trench wall and slate against the brick side too to protect the old brick but still let it breathe.  This big trench takes all the water and it goes away and because it is so deep there is no splashing.  It was specificaly designed to prevent splashback against the walls. There is a shallow border for plants all around to make it safe from falling in and hide it a bit. There is no garden as such its all paved . At thresholds they essentially created a bridge, a sort of small culvert type thing so there was a level threshold with paving right up to the threshold and under it the french drain.

 

There is no problem at all with damp on the walls or drainage it works.

 

I cant find a close up but if you zoom in you may be able to see what I mean, Im not great at explaining it.

 

 

 

Thanks for the info. I understand what you are saying. The front half of the house is 200 years old and im doing similar to you there.

 

Logically i can do the same at the back. Just need a way to soften the visual impact of a big trench! Plants. My wife will be impressed. I like the open space idea, she wants plants everywhere!

[Brickie]

How about a rendered plinth,225mm (3 courses) up from dpc? Be careful not to bridge the dpc though. 

[edsr]

On 28/10/2018 at 19:07, Roger440 said:

 

Ahhh, i see. There is EPS behind that trim. 

 

My issues is the bricks on my house are like a sponge. They just soak up water, hence my concern.

I think you should be OK. I know you can also get a clear weather treatment that makes the bricks less/impermeable and the water beads and runs off (if it becomes a problem). We have an area of block paving that's more or less *at* DPC level (don't ask), and it's working fine. Provided you can achieve a reasonable fall away from the house, (so it doesn't pond) the splashing issue will be minimised. As others have suggested a drain around the immediate edge will essentially give you another 'brick' of depth and prevent any splashing right against the house. Hope this is useful.

Edited April 16, 2019 by edsr

[CC45]

https://www.ebay.co.uk/i/201688875007

 

Few other alternatives out there - see what your local builders merchant stocks

[Andyp82]

Sorry to dig up an old thread but this is exactly what I want to do. Just wondering if this works needs signing off by building control or if it is permissible works.