What is the clean solution to damp in century-old buildings

[sniederb]

We've looked at quite a few old buildings in the last few months, "old" meaning build in the area of 1860 - 1920. All of these buildings have issues with damp. My understanding (but this is more speculation) is that these buildings were originally built with an open dirt floor, so the dampness just went into the entire house and ventilated out. Putting in a floor creates a sealed off space where dampness accumulates and then seeps into the floor and walls.

 

We've seen plenty of statements to the like of "that wall just needs some repointing or similar". This doesn't seem to be fixing the problem, just the symptom. How is the dampness problem in these buildings fixed for good?

 

(Attaching image of one room showing the wood paneling of the original outer wall, along with the typical signs of damp, esp. in the far top corner)

[ProDave]

I see a lot of these old "croft houses" in my travels as an electrician.

 

The walls are typically 3 feet thick, stone inner and outer, rubble / dust core. Absolutely no damp proof course whatsoever in the walls and anything from poor to no foundations under the walls.

 

That one looks pretty original with the wood paneling. Most have been "modernised" first with lath and plaster, and later with plasterboard.

 

the mistake most people make is they line the inside with timber (usually no more than 2" by 2" and board it. Rarely do they put any insulation in, and almost without fail they leave the gap between the stone walls and the paneling open to the loft space so the gap is open to cold air.  On a windy day if you remove a light switch or a socket you are greeted by a howling icy cold blast coming out of the hole.  Most of these come with an EPC rating of E or F

 

I have seen various attempts at "damp proofing" them.  Some paint the stone walls about 2 feet up with bitumen,  On one I installed a "device" that was a small mains powered box that connected to a thin wire laid all around the perimiter at floor level.  Quite what that was supposed to do or whether it worked I have no idea.

 

Do you really want an old cold damp house with small windows?  There are better properties available or why not build a decent house, plots are a lot easier to find up here than many other parts of the UK.

 

 

[SteamyTea]

First thing is to look for any very obvious leaks.

Damp and mould is really the secondary sign there is a problem.

 

Then knock down and rebuild to modern standards.

[Ferdinand]

Sorry - this may not seem helpful.

 

There are quite a wide range of things to know - to do with fabric and structure and preserving them, and where water comes in and out and how it does it. A lot is basics - even as simple as are the airbricks blocked and is the ground level too high. But there is a lot of different things which may or may not apply.

 

It's all the traditional maintenance and renovation stuff, about which there is a library of 840603 books written, then insulate and ventilate in balance - especially if you make it more airtight, and keep it maintained.

 

I think if you look around you will find some renovation blogs which will covers some of the questions each, or perhaps find a 'renovation' book. Or even a course. There may sometimes be something hiding in the detail of Exhibitions.

 

I am not aware of help organisations, unless something like the Historic Houses Association for their smaller house members.

 

If I were buying one (or a big one), and I had questions, I would want a Full Structural at the point I was getting really serious. We actually did that when we *sold* hours, because it was Listed and a right bruiser of a place, to avoid scaring off the customers.

 

Ferdinand

 

[sniederb]

11 minutes ago, SteamyTea said:

First thing is to look for any very obvious leaks.

Damp and mould is really the secondary sign there is a problem.

 

Then knock down and rebuild to modern standards.

I apologize for possibly not getting the humour here .. but would you say that dampness in those old croft buildings is something not worth the effort, and building new is the way to go?

[sniederb]

14 minutes ago, ProDave said:

I see a lot of these old "croft houses" in my travels as an electrician.

 

The walls are typically 3 feet thick, stone inner and outer, rubble / dust core. Absolutely no damp proof course whatsoever in the walls and anything from poor to no foundations under the walls.

 

That one looks pretty original with the wood paneling. Most have been "modernised" first with lath and plaster, and later with plasterboard.

 

the mistake most people make is they line the inside with timber (usually no more than 2" by 2" and board it. Rarely do they put any insulation in, and almost without fail they leave the gap between the stone walls and the paneling open to the loft space so the gap is open to cold air.  On a windy day if you remove a light switch or a socket you are greeted by a howling icy cold blast coming out of the hole.  Most of these come with an EPC rating of E or F

 

I have seen various attempts at "damp proofing" them.  Some paint the stone walls about 2 feet up with bitumen,  On one I installed a "device" that was a small mains powered box that connected to a thin wire laid all around the perimiter at floor level.  Quite what that was supposed to do or whether it worked I have no idea.

 

Do you really want an old cold damp house with small windows?  There are better properties available or why not build a decent house, plots are a lot easier to find up here than many other parts of the UK.

 

 

Thanks Dave. The house is really nice, the location fabulous, but I hear you ... from this thread I'm getting the impression dampness in these old buildings is not something easily fixed, but more an issue you learn to live with. Not the outcome I was hoping for.

[SteamyTea]

1 minute ago, sniederb said:

I apologize for possibly not getting the humour here

I can be a bit off with quips.

2 minutes ago, sniederb said:

would you say that dampness in those old croft buildings is something not worth the effort

Having renovated 3 old buildings in the past, I would say yes, not worth the effort.

In hindsight, the last one I did, I should have gutted out and then dealt with the core problems, the lack of foundation (was a 1860's stable block converted into 6 cottages.  Built on the old beach in Weymouth).

4 minutes ago, sniederb said:

building new is the way to go?

I like modern materials, they can easily be shaped to look like an old building.

It really should not be hard to build an airtight, and therefore watertight, box.  Then add things to make it look pretty.

[SteamyTea]

4 minutes ago, sniederb said:

but more an issue you learn to live

Like asthma caused by the fungi.

[Ferdinand]

38 minutes ago, sniederb said:

Putting in a floor creates a sealed off space where dampness accumulates and then seeps into the floor and walls.

That would see to argue for a new slab infill to make sure there is no such space. 

 

If it is a croft, I will defer to those in Scotland of course. It is genuinely difficult to see what one does with 3ft thick (rubble fill, or solid?) walls, other than seal plus ventilate the inside, and allowing the damp to move outwards.

 

I'm being coy because they are all different. I have a number of places from this period as rentals, and I like them because they are often well-built and predictable, and eg asbestos had not yet been used in buildings. I'd take care eg with Georgian buildings in London because so many of them were thrown-together speculative builds by titled money-grubbers.

 

Quite a few here have restored, and regretted not rebuilding.

 

Now off to ...er .. clear my gutters to make sure it does not leak next winter.

 

F

Edited August 11, 2019 by Ferdinand

[ProDave]

I think essentially building a box inside these houses is the best you will do.  The reason why most are so poor is people use such thin frames and little or no insulation.  If you are going to do a half decent job, then I would be looking at a 100mm frame fully filled with rockwool / earthwool type insulation and them perhaps over boarded on the inside with Kinspan or similar.  That is about the only way you will get half decent insulation, and you will need to pay a lot of attention to air tightness.  I think it probably is important to keep the gap between the stone wall and the inner box ventilated.

 

But can you afford to loose 200mm off every external wall to do that? (50mm gap, 100mm insulated frame, 50mm over sheet of kingspan, 25mm service void, plasterboard)

 

The hard part to detail will be floor joists to keep the inner frame sealed from the gap, and that's before we start thinking of the roof and dormer windows (they are nearly all room in roof)

[DavidFrancis]

Don't know if the contents of this is stuff you already know.

https://www.historicenvironment.scot/archives-and-research/publications/publication/?publicationId=bd396452-624b-4b87-9ae4-a59500b4dff4

[nod]

The best and 100% way of curing damp is to tank the walls 

Not the cheapest but not as expensive as you may think 

 

Below shows a job that I was doing a few week back 

Although this was a cellar With a perimeter drain

Tanking above ground is quite q quick and simple job