Dampness in old house/potential costs

[Kaymo]

Hi,
The backstory here is that my wife has her heart set on a house which has a very obvious damp problem (rotted skirting in one room and visible water droplets in a few cupboards on the outside walls). The house and location are spot on but I am a bit wary of what I am getting myself into and the potential costs of fixing the problems so want to be sure I know roughly how much cash I might need to keep back. Its sandstone walls, slate roof, presumably a raised timber floor (as there are vents on the side) built around 1880.

I'm no expert by any means on any of this but my suspicion is that the problem may be caused by the cement render which is covering the two sides of the house, presumably added to blend in the rear extension which was built about 30 years ago. The cement render comes down to about a foot off the ground and then the sandstone seems to have been painted down to ground level. My understanding is that the paint and render will be preventing moisture breathing out from the stone and instead it is coming into the house.

My question is about the potential costs and risks involved, ballpark figures really to take into account wrt the asking price.

I gather than the cement render will presumably need to be removed from the two sides, and repointed with NHL mortar, and presumably it may also need to be lime rendered if the stone is a mess underneath. Could someone give me a rough idea of the cost of this for an average sized 3-4 bedroom house (2 sides)?

Now, if I am lucky and this fixes the problem and I don't have additional issues with slate roofing, chimneys, gutters etc then I might be even luckier and the house dries out inside and all is well. If I am not lucky does anyone have any idea of what issues there could be and what potential costs could be involved? The big thing in my mind is if the joists are rotted.

Sorry if this is bit of a how long is a piece of string question but I just want to get some kind of ballpark idea of what cash I would need to have in reserve - I'd be taking a 2 year old into the property so can't afford to leave a damp problem unattended for years while I save up!!

Thanks.

 

[jeds]

Cement render is a potential problem but it sounds to me like you really need a whole house analysis. Water droplets in cupboard is condensation and is not directly related to render. A very large percentage of dampness issues that I inspect are caused by condensation. The next largest percentage are roof/gutter/rainwater pipe issues and some are caused by raised ground levels. Inappropriate sand cement render definitely isn't good - but I doubt it is your primary problem.

 

[Kaymo]

Thanks John, I had thought that water that was trapped in the wall and not able to breathe to the outside could condense on the inside of the wall. I think the ground levels on the outside have been raised a bit but they are at least a foot above the floor level inside. I was working on the theory that damp from the ground was rising up because of the impervious coating of paint and render on the outside and breathing out to the inside.

I accept that there could be simpler explanations, like guttering etc, in fact two of the worst spots are where gas and electricity enter the house so it could be nothing more complicated than be poor sealing on these. The problem I have is that the owner doesn't seem to be willing to accept that there is a major problem and there is no hatch to get an inspection of the underside of the house so if we are to proceed we may have to take a risk which is why I am exploring potential costs - so that I know just how much of a risk I would be taking!

Kenny

 

[jeds]

You are right about the breathing wall in the long run but condensation is a much more immediate effect of vapour condensing on the internal cold surface. Lack of ventilation is a major factor along with lack of insulation and lack of heating. Water droplets in a cupboards is a certain indicator. Condensation will be concentrated where ventilation is at it's worse - in corners, behind freestanding cupboards and wardrobes, inside cupboards, etc. In solid walled houses where rooms are not fully used - doors and windows closed, radiators turned off - condensation is inevitable. Much of this will reduce when a house comes into full use. You say the external ground is a foot above the floor level. This is very likely to cause dampness and you should certainly budget for sorting that out. As I said, the render isn't a good thing but I've known plenty of old houses with sand:cement render that functioned perfectly well because the internal environment was used sensibly.

 

[Kaymo]

Sorry John, I meant to say that the ground level is about a foot below the floor, but the vent is almost at the ground level so its definitely been raised a bit. If we end up buying it then I can certainly lower this again, fix any guttering and budget for a roofer to check and repair any parts of the roof that are leaking, but its less the fixing of the problem and more the damage that may already have been done that has me concerned. There was a rotted skirting board that wasn't against an outside wall and I am just concerned that if a skirting is rotted then the joists below it could be rotted. It doesn't look like the owner is going to be prepared to open up the floor for an inspection which is understandable as it has relatively new wood flooring throughout, so I wont know until after buying what the condition of the subfloor is.

I guess this is the crux of my question, does anyone know if joists need replaced is this a hundreds of pounds job, a few grand or much more?

And also, when there is a problem with a rotted joist is it something that you would get warning of from movement on the floor etc, or can they just collapse?!?

 

[jeds]

Floors rarely collapse wholesale. More likely you'd get abnormal movement or sponginess around the edges well before that happened. What it would cost to replace a floor is difficult to say. I'd allow about £2k for an average sized room or maybe a bit more depending on the finish and whether the boards/skirtings can be re-used.

 

[Kaymo]

Thanks John. I thought that would be the case, but I have no experience at all of this. £2k per room is not something i'd like to have to spend but it's manageable in the overall scheme of things.

 

[theprinceofdarkness]

How thick are the walls? A clue here is the size and shape of the window reveals. I have a rock and rubble cottage and despite repointing it with NH5 lime, it still leaks water through the walls.
Frank

 

[Kaymo]

I think the walls were about a foot thick but I can't remember for sure. My feeling is that the water is coming in at ground level at least the visible damp is at this level. My suspicion is that the main issue is the ground level being too high on the east wall as the original vent there is nearly on the ground but there may be other issues as well.