Modern house, internal floor lower than ground?!

RainbowLaura

Hi everyone,

We've lived in our 2001 built house for 5 years with no issues related to this, but I had a bit of a paranoia attack yesterday for some reason and have really got myself worked up.

Down the side of the house is a large, shared driveway which leads to several garages behind us. That ground is, at one end, about six courses of bricks higher than the floor inside our living room the other side of the wall. There is a drain which runs the length of the house, separating it from the tarmac. Our back garden has steps DOWN to the house and small patio outside the doors, both from the side gate (next to the house wall) and the main garden. So the patio (and house) have been dug out of the ground rather than built up. I have suddenly started thinking - surely that's a recipe for rising damp? I then found out about the 150mm rule regarding the damp course - well ours must be WELL below ground!!

I had a look at our homebuyers report and it doesn't really mention anything about it, only that "the main walls have a dry lined inner leaf and outer skin of brick, separated by an air gap. The walls contain a plastic damp proof course". It also refers to the need to cover a small but dangerous gap between the side gate steps and the house, so presumably they did notice the change in gradient and the fact that the house is actually below ground level!

I am now having nightmares that when we go to sell, a more vigilant surveyor might have concerns about this and the house will be unsaleable. Is this a valid concern or am I missing something and it's not a problem?

another_casualty

You had a homebuyers report. Did you not have a proper survey done prior to purchase? Are you planning to move ?
If your home was a new build , what about the 10 year guarantee?

FreeBear

RainbowLaura wrote: »

Our back garden has steps DOWN to the house and small patio outside the doors
...
surely that's a recipe for rising damp? I then found out about the 150mm rule regarding the damp course - well ours must be WELL below ground!!

As long as the soil level immediately adjacent to your house is ~150mm below the DPC, there is no problem. It is only when soil builds up against the walls and bridges the damp proof course that problems begin.

By the sounds of it (steps up to the garden, drain along the side), steps have been taken during construction to avoid sources of trouble.

RainbowLaura

another_casualty wrote: »

You had a homebuyers report. Did you not have a proper survey done prior to purchase? Are you planning to move ?
If your home was a new build , what about the 10 year guarantee?

I considered the Homebuyers Report an adequate survey for a house under 20 years old. Unfortunately the guarantee was a couple of years out of date by the time we purchased. Would rather not move currently but unlikely to stay here forever.

FreeBear wrote: »

As long as the soil level immediately adjacent to your house is ~150mm below the DPC, there is no problem. It is only when soil builds up against the walls and bridges the damp proof course that problems begin.

By the sounds of it (steps up to the garden, drain along the side), steps have been taken during construction to avoid sources of trouble.

Thank you for your reply. The side of the house (about 25 foot) is completely built up to though (the drain touches the wall one side and the drive the other), and our living room floor is a good foot or so lower than the surface of the driveway. It's really obvious when you look out of the window between the two sides. I can't see any evidence of the DPC so not sure where it is

Ruski

RainbowLaura wrote: »

I can't see any evidence of the DPC so not sure where it is

Can you see two different types of brick along the slope of the driveway?

Best to give us a picture

Cheers

Russ

RainbowLaura

Ruski wrote: »

Can you see two different types of brick along the slope of the driveway?

Best to give us a picture

Cheers

Russ

Hi Russ,

Nope all the bricks are the same. I've been doing a bit more research into this today, and I think my main question now is: can the inner leaf DPC be (quite a bit) lower than the outer one? It's the only thing I can think of; that the outer leaf does have one above ground (though I can't see it) and the inner leaf has one much lower. I'm not really understanding why the outer leaf of a cavity wall would need a DPC anyway, as the bricks are supposed to withstand driving rain etc without transferring to the inside? Just trying to educate myself really so I can understand whether I need to worry or not! Thanks for your help

Slinky

It was probably tanked when it was built. Our extension has a gravel path down the side which is higher than the original DPC level for the rest of the building. The builder asked if we wanted the ground level lowered or the walls to be tanked. Given that lowering the ground would have caused problems with a fence next to the path not having proper support, we had the wall tanked. There's a layer of something, presumably plastic that sits higher in the outer course of bricks than it does in the inner course.

If you've never had a problem with damp in this area this is probably how yours was dealt with.

ETA all our bricks there are of the same type and I can't see where it was tanked.

RainbowLaura

Thanks for your reply Slinky, that's a possibility then. It's strange that they'd build from scratch in that way though, I have no idea why they didn't just build the house higher.

I've managed to take a couple of pictures now, showing the side gate steps to demonstrate the height difference. The indoor flooring is about half way down, where the dirty part starts (caused by something being kept down there, which I now know is a big no-no!) It looks like upended paving slabs have been laid all down the side of the house... Which doesn't seem very sensible to me, though of course I'm no expert

lewishardwick

Is the house built on level ground?

Sounds like it isn't so there's been some levelling of the ground for the house only. The drive doesn't really matter if it slopes a bit...

RainbowLaura

lewishardwick wrote: »

Is the house built on level ground?

Sounds like it isn't so there's been some levelling of the ground for the house only. The drive doesn't really matter if it slopes a bit...

Yes the ground is slightly sloping. I'm just concerned that the edge of the driveway butts right up to the wall (well not the driveway itself, but those paving slabs wedged between the drain and the house). It just doesn't seem quite right.

Does rising damp just suddenly become a problem, or would we know by now? We have had some very very wet spells since living here and I've never so much as smelled dampness in the living room - and I have a very sensitive nose.