Damp Proof or Wait?

tightasagnats

Buying 1900 house.

Building survey says ground floor has damp throughout. Also says damp proof membrane is not high enough, and that external render on front of house needs to be removed to a certain level as it's covering membrane. House has been empty 4 years. Airbricks all OK.

Would it not be wise to have the render removed and then see if it dries out before treating? It'd be a bit damp wouldn't it having not been heated for 4 years? There is no smell of damp and one small patch on a wall higher up which is near the porch, otherwise everything looks fine.

Your experiences appreciated! I know surveys always bring up damp in old houses. I don't wish to dodge something that needs doing, but I doubt a damp company would suggest it's fine!

G_M

tightasagnats wrote: »

Buying 1900 house.

Building survey says ground floor has damp throughout. Also says damp proof membrane is not high enough, and that external render on front of house needs to be removed to a certain level as it's covering membrane.

1) remove the render at the bottom so it does not beach the dpc. Or remove the entire render (it's purely cosmetic but can cause problems.

2) Lower the ground level against the external wall eg by digging a shallow trench round the property and filling with gravel.

3) Heat the house.

The walls will dry out.

Would it not be wise to ..... before treating?

'Treating'? Treating what? How?

Remove the source of the damp and the damp will disappear in time.

ProDave

EXACTLY what I had with a previous 1930 house.

Soil level was too high outside in relation to damp proof course. Render was bridging the DPC and to try and hide the damp, the owner had lined the walls with polystyrene tiles.

Hacked off the render to just above the DPC, re formed a new bell cast so water dripped off. Lowered soil level next to the house a bit, and removed polystyrene tiles. The walls dried out perfectly.

tightasagnats

Is this a job for a general builder? My trench digging capacity is limited. Also, where is the current DPC level? How can you tell I mean.

G_M

tightasagnats wrote: »

Is this a job for a general builder? My trench digging capacity is limited. Also, where is the current DPC level? How can you tell I mean.

Yes. General builder or even a decent odd-job-man.

Get several quotes.

Doozergirl

You may not need to dig a trench at all. It will depend on where your DPC is under that render. If your render hits the ground then that is likely to be a problem along with the simple
Fact that it is empty and unheated.

Is it very obvious? Can you see it or is this just a reading from those ridiculous machines?

I would expect the house to smell musty and have a certain level of condensation, if not damp from being unmaintained. I've much doubt it is a failed DPC if the DPC is breached. You'd have to eliminate breach to even consider the other.

You can't remove render without replacing it. If it is sound then only remove what you need to above DPC and replace it, with the renderer using a 'bell bead' to keep water off the bricks underneath.

Your strategy in the OP sounds absolutely right to me.

tightasagnats

Thanks folks that's really helpful. No, you can't see damp, only that one patch I mentioned which seems like a leaky porch, I'm sure it was meter readings but I shall ask the surveyor.

Yes I believe render hits the ground.

G_M

Doozergirl wrote: »

Y

You can't remove render without replacing it.

Why's that doozergirl? I'm not a fan of render - get a slight crack and rain gets behind and causes further problems......

Doozergirl

G_M wrote: »

Why's that doozergirl? I'm not a fan of render - get a slight crack and rain gets behind and causes further problems......

The bricks behind will be utterly ruined by both the render and the tools to remove it. It is designed not to come off.

The best case scenerio would that they lose the protection that the very outside of the brick affords itself. Water gets in, freezes and the bricks spall.

If the house was built to be rendered then there might not ever have been a proper brick bond or pointing. Just stuff that should have ended up in the 19th century equivalent of a skip.

If the house wasn't designed to be rendered, then it's more than likely been rendered to hide sins.

Doozergirl

tightasagnats wrote: »

Thanks folks that's really helpful. No, you can't see damp, only that one patch I mentioned which seems like a leaky porch, I'm sure it was meter readings but I shall ask the surveyor.

Yes I believe render hits the ground.

In that case, you've got this

tightasagnats

House was indeed built to be brick, not rendered, so it's a sin issue as DG says.

How can I tell where the DPC is tho? If it's rendered over....and why remove above DPC? I'm not sure I get the steps. Remove above DPC, install bell thingy to stop water getting bricks wet (am about to google a photo of that) and then you re-render to protect it again...so you do this above DPC as this is where your bell bead goes.

Never saw my life going down these roads but it is interesting.