Old house - Damp issues

[sheikyerbouti]

Hi,

This is my first post on here and hopefully, i'll be able to give my experiences over the coming months.

Myself and my wife have just purchased an old property which, whilst perfectly liveable, has various issues which need sorting out. We knew of the issues at purchase so we are not under any illusions that we need to spend money to rectify.

I'll start with giving a description of the house as i've been doing my research into such things! The deeds are showing a build date of 1919, however there seems to be some features (confirmed by a listed building specialist) that date back much earlier than this, maybe to the mid 18th Century. The house has solid brick walls with (presumably) lime render. It is currently uninsulated. The floors are tile and the house has UPVC double glazing. A fresh air circulation system is in the loft and we have central heating. The house is currently rendered.

The house has an external double garage with a converted 1 bedroomed annex on the end.

Ok, we enlisted the services of a specialist in listed and period properties before committing to purchase. After taking various probe readings and getting information on the property, he recommended the following :

- To ensure that the ground level all around is sufficiently below the bell render to allow drainage.

- To rerender the property in the correct materials (lime)

In his opinion, these were the only issues to address to get the property in fine shape ready for modernising inside. He was a very knowledgable chap and I trust in his knowledge and experience.

The previous owner confirmed that the property had suffered with leaking gutters for many years which were replaced about a year ago. Various roof tiles have also been replaced which show that there has been issues with water in the past.



We moved in to the property last Saturday and are now able to get a good look around and get quotes for building work. I got a local builder who I have used before (40 years experience) and, again, whose knowledge and expertise I wouldn't question. He recommended having the following completed:

- Extend the roof overhang by around 50-100mm to help stop water running down the wall,

- Rerender in Sand and Cement - In his opinion modern day materials are breathable enough for what I require. If, however the brickwork is in good condition after stripping off the render, he would recommend the walls be treat and repointed (in cement mortar)

- Inject a DPC as the internal damp issues are rising damp. He was very insistent on this. Strip off all plaster to a metre and replaster.

- Some kind of french drain at the side of the house (this land does not belong to me and is a car sales pitch - however i'm sure some works could be done to help alleviate my damp problems)

- Repoint chimney and check flashings.



I'm awaiting a quote for the above.


Now i'm confused. I want to do this job right and feel I am appraoching it correctly - tackle any building works and make the place watertight before starting and internal fancy works! However I want to ensure the structure of the building will be correct for years to come. I wondered if anyone would like to give their opinions on what I have been told?

I've attached various pictures at the following link for your perusal - http://imageshack.us/g/84/outerhousekitchenwall.jpg/
Also, can anyone recommend a traditional builder in the Yorkshire between (Selby and Doncaster) area?


Many thanks



Russell

 

[sheikyerbouti]

Thought I would add,I did some digging around last night.

I wanted to take a look behind one of the many cracks in the internal plaster to ensure no issues. I dug the plaster out above a window and found the house has wooden lintels. The one I checked was dry and solid.

The next hole I made was about an inch above the skirting board in some perished blown plaster. I didn't hit the brickwork, however I did hit a soft layer of black plastic, the consistency of hard chewing gum. I presume this is a dpc that has been injected in the past. This was also entirely dry.

To correct my above post, the house has features dating back to the mid 19th century, not 18th

 

[MatthewC]

The house has solid brick walls with (presumably) lime render....

...I got a local builder who I have used before (40 years experience) and, again, whose knowledge and expertise I wouldn't question.

Sounds OK so far, but check that it definitely is lime render

He recommended...

- Inject a DPC as the internal damp issues are rising damp. He was very insistent on this. Strip off all plaster to a metre and replaster....

Oh no. No, no no. There is lots on this forum about this and my view would be that if he insists on an injected DPC, then he is the wrong builder. He who pays the piper calls the tune.

By all means strip the damp soggy plaster off, but look for the causes of the dampness, sort them and wait for it to dry naturally. I have proved this approach on my own house (see http://houseintheenchantedforest.blogspot.co.uk/), and many others on this forum have similar experiences.

 

[sheikyerbouti]

Thanks for your response.

It's a dilemma when a builder who you trust is giving conflicting advice to what seems to be the norm with old houses!

As the house already has a damp proof course in, would it make a difference to put another one in?

Below is a picture of the hole I dug out - I suppose it proves that these DPC things don't always work!

 

[Flyfisher]

In my amateur view I'd say there is one missing element in the proposed options . . . . Time.

It sounds like the house has suffered from a number of minor problems that have allowed damp to build up over some time. Leaking gutters can put a lot of water into walls and raised ground levels are a bit of a no-no. It's understandable that any new occupier would want to fix things quickly, but there's a difference between quickly fixing real faults and allowing the house to gradually reach its new equilibrium - which is where time comes in.

I would aim to fix the fundamental faults first (sounds like a lot of this has already been done) and then give the house some time to see how it reacts. We have the prospect of a long dry summer ahead and the house could be very different in six months time. Plus, you'll have the benefit of understanding a lot more about how the house 'works' and will be in a position to make better informed decisions as necessary.

 

[FamilyWiggs]

This is my first post on here and hopefully, i'll be able to give my experiences over the coming months.

Welcome the the forum, Sheik. I assume you are the brother of Dji?

- To ensure that the ground level all around is sufficiently below the bell render to allow drainage.

- To rerender the property in the correct materials (lime)

In his opinion, these were the only issues to address to get the property in fine shape ready for modernising inside. He was a very knowledgable chap and I trust in his knowledge and experience.

Well, he sounds spot on. Sort out the causes of damp and then let time take its course before further changes. Ground levels, removing cement coverings (and re-rendering in breathable ones) and fixing rainwater goods are all first priority.

The previous owner confirmed that the property had suffered with leaking gutters for many years which were replaced about a year ago. Various roof tiles have also been replaced which show that there has been issues with water in the past.

Yep - that should help!

I got a local builder who I have used before (40 years experience) and, again, whose knowledge and expertise I wouldn't question. He recommended having the following completed:

- Extend the roof overhang by around 50-100mm to help stop water running down the wall,

Hmm - if the guttering is working properly, not sure why this would be necessary?

- Rerender in Sand and Cement - In his opinion modern day materials are breathable enough for what I require. If, however the brickwork is in good condition after stripping off the render, he would recommend the walls be treat and repointed (in cement mortar).

NO NONONNONONONONONONONONONONON NO and NO. Cement is not and will never be breathable. You have solid walls, you need the house to breathe. Cement is fine for modern cavity constructions where the cavity provides the protection. Cement is not the right thing for a solid wall. It tends to trap moisture behind it making the wall wet.

- Inject a DPC as the internal damp issues are rising damp. He was very insistent on this. Strip off all plaster to a metre and replaster.

If he "insists" on this, then insist he is not the right builder for you and walk away. He doesn't understand your type of building.

- Some kind of french drain at the side of the house (this land does not belong to me and is a car sales pitch - however I'm sure some works could be done to help alleviate my damp problems)

This may be helpful - but it you have lowered the ground levels to a foot below the internal floor levels you may not need to do this anyway.

- Repoint chimney and check flashings.

If there is problem, then this is sensible. Dependent upon the bricks used though (is the stack original for example), it is probably better done in lime mortar and not cement. Cement mortar is generally harder than the stone or brick it is attached to, and will damage softer bricks and stone over time. I know this because I can see the damage it is doing to my own lime/sandstone walls. Bricks can be very soft too - especially older types.

Now i'm confused. I want to do this job right and feel I am appraoching it correctly

That's the correct approach - deal with the immediate causes of damp and then wait. If I were you I'd be doing the rainwater goods and ground levels and stripping off any cement render and then waiting until after the summer to see if there is still a problem, and then proceeding from there. I wouldn't be worrying after a week or two in the place.

Your surveyor sounds like he knew exactly what he was talking about - if he is local, maybe ask him if he can recommend a more sympathetic builder or two?

Hope this helps. Others more knowledgeable will be along shortly...

 

[plasticpigeon]

Hello there

I'm not a builder or surveyor but here is my 2 pence worth!!

I'm afraid to say that although your builder may be a very good builder it sounds like he is suggesting methods that are not appropriate for an old house with solid walls. I personally think injecting a damp proof course is not a good idea, and replastering up to a metre (presumably in cement) is only done to hide any dampness, it doesn't cure the problem. Unfortunately this has become accepted practice but for bad reasons. Namely surveyors don't want to comment on damp as they don't want to get sued by a client if damp is found elsewhere in the house or if their suggestions don't work. They generally therefore pass the buck and recommend a specialist. This specialist is almost always a contractor that has a vested interest in selling treatments, and boom, there you have it, every house needs an injection. This practise has become so common is it just generally accepted, but it is not good practise. Your listed building specialist didn't recommend any injections or cement and I think he is correct.

It looks like you have some impervious coating on your walls at the bottom (the black paint). Although this seems a good idea, the general consensus is that if there are cracks in impervious coatings and there almost always are, these cracks let water in, and the coating stops evaporation and holds it in the brickwork, a bit like putting a wet towel in a plastic bag. I would imagine the walls are probably cement rendered too which may or may not be a problem but if you want to and are able to strip the render off I would strongly advise leaving the brickwork exposed.

If all the sources of damp, ie roof leaks, guttering, ground levels and drains (have they been checked?) have been sorted then perhaps just wait for a couple of months to see if things improve!!! I think one word of advice is to avoid using cement on old buildings.

 

[FamilyWiggs]

Ooh - I've just looked at your pics. Looks like a good example of why coating a solid-wall building in cement/masonry paint leads to a damp building.

 

[JoceAndChris]

I think you've had some excellent responses to your post, and just to reassure you, we had a very similar experience with the damp merchants peddling the horrific "cures" you describe. Fortunately I found this forum in the nick of time. Nearly 4 years on and we've retained the lovely old wobbly lime plaster that characterises much of the inside, and damp isn't an issue. Unfortunately our house was caked in exterior cement render as yours appears to be, we've removed the worst affected areas and solved the inner damp by doing so. We intend to get the whole lot removed and rerendered in lime when we can afford it.

Your money would be much better spent on sorting out some nice timber windows, rather than measures that won't do any good. It would be nice to think your cement render can come off and leave the pretty brickwork exposed, but I've yet to see a house where such a thing has worked. Typically, the render usefully covers botches and alterations and it's removal leaves a white residue that can't be shifted. Also a stucco covering might have been part of the original design. I'd be looking at rerendering in lime but only after a few years of living in the building and seeing if it really needs it.

 

[MdB]

Builders for the last 80(?) years or so have been told that a layer of cement is what you need to keep water out. It is well ingrained into them that it isn't questioned and you will find very few builders that believe that anything else is sensible (and will argue this strongly). The idea that this ability to keep water out also is very good at keeping water in isn't questioned unfortunately. They don't see the results of their work 5 / 10 / 50 years down the line when the damp has set in and rotted any wood buried underneath and plaster is falling off the walls so don't learn.

We bought a house that was very damp. I took the advice given here, got rid of the cement, repointed in lime, didn't put a injected DPC in (which is laughable) and now have a very dry house (apart from the concrete 1970's extension but that is another story).

 

[Moo]

It looks, from your photographs, as though some of the render is already parting company with the house. If it were mine I wouldn't be able to resist picking at it!
That poor house has been really badly treated, hasn't it? If you hadn't told us in your first post, I'd have thought it was one of those cheapo council-houses that were thrown up in the sixties.
Yes, the walls will look a bit of a mess when you've got rid of the render, and you'll probably want to re-render (in lime, of course). But in the meantime you'll get some idea of the shape, size and position of the original windows and doors.
Go on - do get going with your bolster and chisel and see what treasures you uncover!

 

[JohnB]

My house is stone with clay mortar, but some of your photos look very similar to mine. I can't post any photos at the moment as my broadband is currently painfully slow.

Outside walls are cement rendered, with a plinth of soft cement. Nearly all of it comes off quite easily as it's not firmly attached to the stone, but is firmly attached to the botched up stone/brick with cement mortar where windows have been moved. The plinth stuff also falls off easily. There is a concrete path on inside floor level. The lower part of the walls is damp, and damp has got in where the render has cracked. Old houses are built to move, but cement isn't :evil:.

The inside walls downstairs are/were covered with an inch or two of cement, and are damp underneath. Some of the joist ends, and other bits of timber in the walls have rotted. Upstairs, the walls are mostly dry lined, with inch battens and 12mm plasterboard on top of the original lime plaster. The small bits I've removed so far are damp underneath. According to my tame conservation builder, latest research from the Building Research Establishment is that dry lining is a big no no. The walls behind get damp, and the battens and plasterboard rot. Mine hasn't rotted yet, but it's only been there a few years.

All downstairs floors are concrete, and one formally external wall has a 1960s extension on it, and is damp at the bottom.

Having downpipes that deposit rainwater at the base of the walls probably doesn't help!

I'm working on removing all internal and external cement and drylining, and replacing with lime/limewash, although as I have a former clay pit, I'd like to do some internal walls with clay plaster. I'll also remove outside concrete paths, and lower the ground level. Rain water will end up in big tanks, like IBC containers and fruit juice containers, for garden watering etc (it still rains in Wales!).

Hopefully I'll end up with a dry house that no longer looks like a pair of 50s council semis!

 

[castiron]

Hi - we get asked alot about condensation and damp so I'm well read on the subject.
Can I recommend a book by Alan Oliver - Dampness in Buildings.

It's informative and technical without being over complicated, regards adrian

 

[sheikyerbouti]

Many thanks for all your help so far.

Had a chap out yesterday who "does lime" apparently. I wasn't overly impressed but i'll see what his quote is like.

Annoyingly, he pulled a chunk of the outer render from the wall in a very conspicuous area! I suppose he needed to see what was underneath, but he could have asked or at least remove a bit you don't see!

Anyway - here is a picture of what is under the render......

I don't know what you can tell me about this render, but does it look like Lime based to you?

On another note, I may have found another source of the damp issues in the house. It seems there has been a damproof course inserted at some point. However, this seems to be currently about 3 inches ABOVE the render line of the house. Would this cause an issue?


Many thanks!

 

[Zebra]

I don't know what you can tell me about this render, but does it look like Lime based to you?

I'm sure others will give you a more definitive answer, but I reckon that looks like some sort of weathershield masonry paint, not breathable at all. Underneath it looks to me like a cement render.... How hard is it, the layer under the paint?

 

[sheikyerbouti]

Thanks for your answer. I'm 100% sure the outer layer is an impermeable coating - this will definately be coming off! it was completed in 2002 and I have the receipt from the previous owner.

However I don't know if this was just a blowover or the coating below was also added at the time. It seems pretty hard stuff.

I work at a power station which utilises an FGD unit - we use limestone to clear out certain toxins from the emissions. I'll see if I can sweet talk the lab guys to analyse a sample of render for me to see if any lime is present. (A blue riband or two should entice them!!)

 

[MdB]

I'll see if I can sweet talk the lab guys to analyse a sample of render for me to see if any lime is present. (A blue riband or two should entice them!!)

You can do a quick test yourself by dunking a sample in vinegar.

No fizz = cement
A little bit of fizz = probably cement
A lot of fizz = probably lime

Have a mate with a big lab to play with is better than your own test by a long way though!

 

[AMc]

Boring warning - if you strip off all the render then you may need to insulate the wall (internally or externally) to meet building regulations. Some people avoid this option by not telling Building Control or can use listing to avoid it.

Repairing a thermal element is often defined as replacing less than 25% of the overall area, more than that is considered renewal and may require upgrades to meet Part L1B of the regs.

External insulation will make your house warmer but will require changes to the window sills and the roof line as it adds depth to the wall externally .
Internal insulation will require changes to the window boards (aka window sills inside) and may affect other original features like skirtings, coving and picture rails internally

Make sure you and your preferred contractor have thought this through BEFORE they start to strip the render.

 

[MdB]

Boring warning

Very true. My neighbours had to insulate the inside of their house because BC noticed that they had removed the render. They were not too best pleased.

 

[AMc]

And either type of insulation may make your damp issue worse if inappropriate materials or techniques are used.