damp again!

[welly]

Hi, I’m a new member so forgive me if this is going over old ground! We have just bought our first property, a modest 1870s terrace in need of complete modernisation. We are on a budget which stretches to diy only! So, if anyone out there has a solution to our problems, it would be great if you could include product recommendations and/or or a blow-by-blow account of how to tackle the job.

Ok, the situation is that our ground floor is damp. I was going down the route of DPC and concrete flooring to include DP membrane but then someone suggested I check out this site first. Having read some of the previous discussions on the subject, I can see that my plans are likely to attract …. er ‘negative feedback’ I’m all ears when it comes to alternatives as many suggested solutions seem also to be cheaper and less work which is fine by me!

The existing floors are mainly quarry tile directly on sand. The hallways have about 1 inch of cement. It’s all damp and I don’t mean the surveyors damp metre says so type of damp – noticeable wet patches on all floors. Plaster was falling off, the skirting was totally rotten and the bottom of the doorframes and stairs are going the same way. DPC has already been done and to be fair has dried out the walls. We are now looking for a way forward with the floors. We have been here for a few months now (living upstairs) and, unfortunately, I don’t think that it’s just going to dry out or that it is moderate enough to live with. We have checked for causes such as outside ground levels being above floor levels and dug down to check for leaks on a couple of the worst areas but found nothing. Any ideas? Or will it have to be concrete after all?

Once the floors are sorted, all remaining ground floor joinery is suffering from some sponginess / rot at the base for a couple of inches (has been checked – no dry rot thankfully!). Does anyone know if it’s possible to treat and/or fill the existing doorframes and bottom couple of stairs, or is it a rip them out and start from scratch job? I’m assuming this is a complicated and expensive job best avoided if at all possible?

If anyone managed to get through all that and is still awake, well done and thanks for reading! Any advice will be massively appreciated.

 

[SD]

I'm no expert and I can't advice on how to tackle the source of the damp but once sorted I would stick to 'less is more theory' with the timber I would imagine that the spongy wood would have to be removed and new wood 'spliced in'. (just like timber windows) but I wouldn't rip out everything. Get a joiner/carpenter for a quote/chat and you'll be able to determine how much of it you can do yourself and how much you would need to leave to the professionals.

 

[welly]

Thanks on the timber advice. Unfortunately we are too broke for professional help. Could do with knowing how / if to treat remaining timber once rotten stuff is cut away.
Going back to the damp thing, old threads always seem to suggest the 'get rid of the source and it will dry up' approach. However are there not situations where there is no underlying fixable reason - I don't know, maybe something to do with ground water table levels? As I said, we can't find anything to fix, the rest of the house is dry with no condensation problems, just very damp floors. So I guess I’m asking is the dreaded damp proof membrane sometimes the only solution?
Sorry again, I know the subject has been done to death but I’m really stuck on this one.

 

[chuckey]

Have you dug any holes in the garden/yard?. This is find out the water table level, i.e. if you live in a valley, ground water will find its way to within a Gnats c**k of you floor level. The classic way around this is to dig out french drains around the house (a bit difficult in a terrace).
As hard up as you are Tiles on earth do not make a very dry and warm house. They must be attended to sooner or later. If you want to keep the tiles, I would dig them all up, clean and store them, remove about 3" of the "soil" and dump. Lay a DPC membrane, then 2" of foam insulation, 1 layer of 18mm flooring grade chipboard. This is a cheapo floor, re-lay the tiles on the chipboard for the desired effect.
If the wood has a solid core, chisel off the rotted stuff, square it up, nail on suitable bits of new wood, using a waterproff glue. Fill and sand - bobs your Uncle!
Frank

 

[Nemesis]

Of course, the water could well rise up the walls as it needs to go somewhere...

What sort of DPC was installed? Has it dried out the walls, or has it masked damp?

 

[pieman]

Speak to your neighbours and see what they have done if anything to fix the problem.

 

[Moo]

Tiles on earth do not make a very dry and warm house.

Almost the entire ground floor of our house is tiles (pamments, to be exact) or flagstones on earth and it's very warm and cosy. And dry.

Discuss.

 

[Matt Green]

Thanks on the timber advice. Unfortunately we are too broke for professional help. Could do with knowing how / if to treat remaining timber once rotten stuff is cut away.

Isolate it from the floor with a membrane of some sort or slate.

Going back to the damp thing, old threads always seem to suggest the 'get rid of the source and it will dry up' approach.

DPC has already been done and to be fair has dried out the walls. We are now looking for a way forward with the floors.

What do you mean by "the DPC has been done...?"


Matt

 

[welly]

Apologies if I wasn’t clear about the DPC. I had already done this (silicone based injections into a mortar layer) before I realised there may be better alternatives. The plaster was stripped for a few weeks before the injecting was done and the brickwork remained damp. After DPC it dried up pretty quickly and we then re-plastered, so as far as I can tell it was effective rather than new plaster just masking the problem.
I’m now concerned that if we lay a concrete floor with DPM, might it divert moisture and put extra pressure on the DPC in the walls causing it to fail?
Was interested to read the floor structure suggested by chucky. However, wouldn’t the results be the same as laying concrete because they both involve a DPM? I haven’t priced materials yet, so perhaps this alternative was suggested purely to reduce cost (and digging)?
Final thing on the rotting timber - I’m just wondering if drying it out (assuming we sort the floor issue) and cutting away the brittle stuff will be enough to stop it recurring or do I also need to treat the remaining timber with some sort of hardener or preservative to be sure? Also, is there a product that anyone knows of to fill and neaten up the joins where new and old meet?
Sorry I couldn’t shed any light on how the neighbours have tackled the problem. Drill holes are visible, so obviously they have had DPC work. To find out how successful this was would involve my learning polish, which is probably not the easiest way forward.