Hello everyone :) Damp Damp Damp!

[Damon]

Hi all,

I've been lurking here for a while and have learnt alot from you knowledgable fine lads and lasses! Thanks

I'm in the process of buying + renovating / restoring a nice little semi derelict cottage from 1901 which is safe to say is a bit damp. It's unoccupied and has been for months so is very cold and damp!

The surveyor recommended that a DPM should be installed in the ground floor. The house has no DPM or DPC at all which isn't unusual for a house built around this time.

The floor in question from what I can make out is brick/ tile laid straight onto the ground. My question is, should I lay a DPM or not? My current thoughts are that the house needs to breath and by laying a damp proof membrane the damp will just get pushed into the walls. If a DPM is the right thing to do, should I dig up the tiles, lay the sheeting and then concrete + screed or would more modern liquid DPM work over the tiled surface. Insulation will be laid over the floor and then I have some lovely reclaimed maple boards from an old tobacco factory to fit.

I am going to lower the outside levels and get the house ventilated and warmed up. I also have some guttering to fix, a bit of flashing to sort out and damp lime paster to remove!

So guys/girls... What do we think? DPM or not?

Thanks very much,

Damon

 

[Me!]

Hello and welcome.

I have previously lived in a 1906, brick built, semi-detached. In that house various previous owners had attempted various "improvements" over the years, including painting thick bitumen on a couple of the downstairs floors and replacing another section with modern concrete flooring. The dampest walls in the building were the ones next to these "improved" floors, and the walls in rooms that hadn't been messed with were fine.

And I imagine that is the sort of answer you were expecting to get on a forum like this anyway

But seriously, as you know you've got things that need doing to gutters, flashings and ground-levels, then please do all those first, then wait a year to see what impact that work has had on the damp before considering anything more drastic.

However, if you definitely do want to fit your maple boards then I doubt you will be able to do that on top of any existing floor even with a bitumen coat first. I've seen that tried before with oak boards on an old floor and the damp was sufficient to make the boards keep cupping and moving as their moisture levels changed.

I hope that helps, and good luck.

 

[malcolm]

My house had been open to the elements for a year when I bought it and there was water dripping down the walls. I got the heating running and opened the attic window to let the house dry and ventilate and the house became reasonably dry in a few weeks. Is your house liveable enough to do that? If so it will save a lot of expense if you live with the house for a while before making drastic changes.

If you put a damp course under the floor the ground will become saturated under the damp course so the base of the walls can become damp. In a modern house the damp course would go through the wall to avoid this issue. Waterproofing the walls would just make them wet.

Lime plaster should not need to be removed when it gets wet. Unlike modern plasters it should dry without damage.

 

[Flyfisher]

Assuming the house has been empty for some time, it will have reached an equilibrium with its current environment, ie unheated and, depending on how 'semi derelict', possible water entry. Also depending on its construction, it may take a considerable time to reach an equilibrium with a new environment, ie internal heating, fixed leaks, normal occupancy etc. A widely touted rule of thumb in these here parts is that damp walls can take one month per inch thickness to dry out, so it can be appreciated that we're talking many months, perhaps a couple of years for the house to fully adapt to a new environment. As per the above posts, this is to suggest that things should not be rushed and that 'quick fixes' are unlikely to be the best approach.

As for your floor, why not leave it as it is? We have a room with pamments laid directly on the ground. The floor is dry to the touch but if covered then damp will accumulate underneath the covering. We discovered this after storing cardboard moving boxes in that room for over a year. When lifted, the bottom of the boxes disintegrated in a mush of damp cardboard while chairs, tables and other furniture standing on the same floor were completely unaffected because, being raised above the floor, they hadn't trapped the small amount of moisture seeping through the floor - a valuable lesson about the importance of ventilation and allowing old houses to breathe. Imagine covering that floor with a dpm and trapping all the moisture clearly present instead of allowing it to harmlessly dissipate.

Having said that, the floor is cold and our other ground floor rooms have had suspended wooden floor installed - presumably for this reason. They are not original to the house but certainly very old. They have been installed over the plain ground using simple bricks and tiles to support the joists and then covered in boards. The floors are in good condition and in the places where I've delved beneath the boards the soil is bone dry to the touch. Our soil is quite sandy and a handful of it will run freely through one's fingers, showing how dry the underfloor soil really is. This, I believe, is due to the good ventilation below the suspended floor.

All of which is a long-winded way of suggesting that a suspended floor might be the answer to the floor question. Leave the existing floor untouched and lay a suspended floor above it. Use simple bricks to adequately support the joists while leaving lots of space for airflow and install sufficient airbricks or pipes to ensure good underfloor ventilation. If the room has more than one external wall then so much the better as small wind-induced pressure changes around the walls will enhance the ventilation.

Having said that, I would still be inclined to live in the house for a while before making major changes. I realise the convenience of this will depend on personal circumstances but it would allow time to learn how the house really 'works', time to properly think through your plans, and time to fix any immediate issues such as slipped roof tiles, old flashings, dripping guttering, etc, etc. Old houses are usually old because they are robust. They may be in need to some TLC but it's unlikely they are in imminent danger of collapse and slowly doing the right things is usually far more important for their well being than quickly tarting them up with inappropriate modern materials.

Good luck with your new project

 

[MatthewC]

I support all the above advice. In summary and from my own experience, there are two things you should do before doing anything drastic:

1. Address all the causes of dampness (NOT the symptoms).
2. Wait for at least a year and then think again.

The only drastic thing I would do at once, if appropriate, is to lay a limecrete floor, as doing that after you have moved in would be a real pain! Please do not install a DPM until the house has been given a chance to work as it was designed to. My house does not have one and doesn't need one, having done the roof/gutters/high ground/downpipes/drains.

Matthew
PS see my blog - click the Contact thing on the right, then the blue spot

 

[JanJonWestWales]

yes as above...
1. move as much water away from the house as possible. Check gutters, downpipes, side drains, undergroud pipework if you can.
2. Air the house well, and see if this helps
3. dont panic and dont rush ro a solution(nothing going to go drastically wrong,
4. Explore options...DPC is not a favourite around here, but there are alternatives (Limecrete for me)

good luck and keep us all up to date on progress

if you want to see what can be acheived with breathable walls and floor (and the assitance of an extractor fan)....see my blog, where I limed a basement which had a stream flowing through it, and its dry (ish) !!

 

[Damon]

Thanks very much for the replies. Much appreciated and all taken on board!

Jan/Jon I'll check out your blog shortly. I'm sure it'll be invaluable when I come to make choices.

I'm going to take everyones advice and just get in the house and get it repaired + aired. Once I've been in there for a few month and got the place plumed and wired I'll make a final decision on what's the best course to take. No DPM though for sure!

Ideally I'd still like wooden floor downstairs as the tiles will be rather cold underfoot. Can you lay a wooden floor on a solid base of limecrete with cork insulation in-between? A suspended wooden floor is also an option I'll look into nearer the time.

Thanks again for the warm welcome and quick replies. I'm sure once I'm in I'll have about a 100 more questions

Best Regards,

Damon

 

[livias]

If you go for the limecrete floor option then put underfloor heating in the limecrete floor and then your tiles will be lovely and warm underfoot. No need to waste wall space with unperiod radiators