installing airbricks, damp proofing and insulated plasterboard 1914 solid stone walled house

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what..the? | 15:20 Wed 04th Aug 2010 | Home & Garden
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There is obvious ventilation issues, the house is being renvoated with new roof etc which are causes of the damp. Drip feeds are being added to the double glazing but I still feel this is not enough as we go out to work and shut the house up, drip feeds wouldnt be enough. I have been told by a project manager that adding ventillation to the walls via airbircks would be very difficult with a wall like this and also it would be impossible to damp proof walls of solid construction. He has also steered me off installing any type of insulated plaster board on the walls. My lifestyle does create moisture as every house I have ever rented has had damp and mould problems a part of me thinks it is just me causing it on half the occasions, I open all the windows use dehumidifiers but quite frankly I still suffer and now have a mould allergy and on inhalers. Please if possible does anyone have experience of knocking vents and putting air bricks in walls, damp proofing or adding insulated plaster board to wall of this type and age. Thanks in advance


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I don`t have experience but I have a 100 year old house that I rent out and as you say lifestyle has a lot to do with things. My friend is a surveyor and whenever a tenant has said there is damp he says it`s a lifestyle issue. Old properties have to be ventilated and heated. Lots of tenants do things to save money such as not putting the heating on etc. As my house has no outside space, people put washing on the radiators which causes condensation. Having said that, I do have a few rising damp issues with the place and if I decide to keep the house, I`m told cement based tanking is fantastic so you might want to look into that. I`m sure someone with expertise will come on here later and advise.
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thanks for your answers it's nice to know I am not alone, never heard of cement based tanking so I will look into that, thanks again.
How long have you got Whatie" Lots of things to consider here.
Through the wall vents would work nicely, but, in the winter when they're needed most, people tend to bung them up rather than suffer a blast of cold air around the feet.

Google "Passive Stack Ventilation" .............. read up about it .......... could be just what you need. Used mostly on new build, but can easily be retro-fitted in houses like yours.

Couple of other points that I have to stick my neck out over ...........
1 Damp-proofing older solid-walled houses is never impossible. You just need to pick the right method and apply it properly.
2 Insulation IS essential, but must be teamed with good ventilation to be completely effective.

I answered a Q recently, outlining a widely used method of putting up insulated studwork walls "within" your existing walls. I'll go back over my replies and see if I can find it.

Cement tanking ............ I've used the "Vandex" system many times over many years. There are others. I'll see what I can find.
Bitumen barriers such as "Sythaprufe" and "RIW" have been around for years. They are just finished with "Carlite" plaster in the conventional way.
There are so many ways. If you could have seen some of the old dilapidated stone barns I have had to damp-proof, insulate, and convert, I think you would be pleasantly surprised :o)))
Lol............. I've just found my reply to the Q about insulating walls ............... it was to you!!!


I've just read your other Q about Rayburns. It got me thinking .......... if you're going to visit the house intermittently, I would seriously consider the internal studwall approach I outlined in that Q. The reason being............ you would have a much more rapid "warm-up" time considering you could be driving down to a relatively cold house. Uninsulated stone walls take for ever to warm up initially. You do get a wonderful "heat store" advantage, but with insulation on the inside, you only have to heat the air, NOT the stone walls. "Lifestyle" issues again.
...... ongoing ...............
looking back over that earlier insulated studwork reply, I must have missed your final questions ............... here goes ........
The "cavity" between the studwork and the stonework will remain a "damp" environment. Crossflow ventilation to the outside air can easily keep the void healthy, without transferring any damp to the inner "skin".
.............. and ...... finally ............... thickness of stud wall plus 50mm cavity ........ say 150-180mm lost from the width or length of the room ........... for each outside wall :o)))
Providing the floors are dry and membraned, and not tiles on earth, you have choice of re-plastering lower 1M of walls with a backing membrane....
or you can knock the plaster all off back to stone/brick .. and use Thoroseal ... http://www.thoroprodu...cts_waterproofing.htm

This really is the best for old properties .. it is a cement based product, well known by councils, Heritage, and other big organisations. It can be applied to even wet walls. It is Base/top coat plastered on top.
Insulative layers won't work for long, and will cause damp smells through the house.
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thank you so much for your help, this guy I got round who is a project manager and a chartered structural engineer he said to him even though there was only damp in two of the walls I considered removing all the plaster from all interior sides of exterior walls and replastering with insulated plaster board or stud walling it what with my lifestyle issues creating moisture and my mould allergy I thought it would be better and less likely to get cold walls = condension and also lower heating costs. He said all the walls are fine, there would be some investigation into the cause of damp in the two walls (likeyly roof) and this would be fixed, wall then replastered but other than that he just says we need to redecorate. he said no also to the damp proofing and airvents. But all the above are things I thought would make the walls and house warmer, more ventilated when needed and cheap to heat so I am at a loss when people say on here something else. The whole house is being renovated for not less than 100k roof, plumbing, kichen, bathroom, balcony, parking and decoration but he said the walls should just be left as they are a heated well, but if I am out to work 9-6 it would be annoying to heat the house all the time when I am not there.

Thanks 'builder' for looking into all the past posts
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Spelling error...

he said the walls should just be left and they should be heated well instead, but if I am out to work 9-6 it would be annoying to heat the house all the time when I am not there.
Mmmmmmm ............. uninsulated solid stone walls ........ well heated. I wouldn't like to start an argument, but you'll be the one with the heating bills.
In Building, as with everything else, there are many, many solutions available. Heatstore versus rapid warm-up? As I mentioned above, rapid warm-up involves plenty of internal insulation, so you only need to heat the air, not the building. Using the stone mass of the building to store heat, say from centralheating coming on for a couple of hours in the morning, would be fine. In the evening some of that heat would still be radiating from the warm walls. The trouble is, a great deal of the heat plus any you apply in the evening, goes to waste through the uninsulated walls.
The way around that would be to put the insulation on the OUTSIDE of the building.
I've done that before, but only when the external render was due to be replaced anyway.
Project Managers and Structural Engineers ........... I know, I know........... how can I put this diplomatically? .............. They can be a tad "precious" about a project......... stating their preferences maybe a little too dogmatically. There are many solutions. It should be remembered that the whole point of the job is to give the customer the service and the product that the Customer wants.
Question Author
interesting what you say about outside insulation I have heard about in europe they put polystirene on the outside walls but this does mean moving things like windows and steping them out etc. I wonder the cost, whats the uk name of this or similar. the rendor looks ok but we are re-roofing with new pv facisa and downpipes, checking render and painting with scafold up. Of course I have not chosen to go with said project mamager yet as he does all the suveying an drawing at and non returnable 3k so I am making sure I want to use him first. He has been recommended by 1 person, he seems good and quite frankly theres no one else trustworthly so the choices arent endless
There are specialised products available for "outside" insulation, but honestly, I've never found the need. Without going into horrendous detail here .................... for a decent thickness of insulation, I've simply fixed 100mm timber studs to the wall face and cut 100mm thick "Celotex" or similar insulation boards between the studs. "Tyvek" or similar breathable fabric is stapled over the whole thing ............. followed by galvanised wire mesh .................. then sand & cement render applied in the usual way. Finish is exactly the same appearance as just rendering the bare stone.
There is a "deluxe" method where plywood is nailed over the studs, then breather paper, 25mm thick treated battens nailed on, then the "Tyvek", wire and render as before. This provides a 25mm "draining cavity" between the render and the studs/plywood.
No need to move windows, door openings etc ............. it's then an aesthetic consideration re the increased depth of the window reveals. Most reveals are too shallow anyway.
.................... and I forgot to say ............ if you're re-roofing, it's no big deal to plant timber on to the rafter ends to increase "overhang" if necessary.
Question Author
just wanted to come back and say a big thank you for all your help the project manager has taken the stud walling ideas and is running with it so I am so happy I dont know about if the void will be ventillated yet but they will be insulated with vapour lock both sides.

Outside insulation looked to more difficult option as the render currently is in good condition but I appreciate your advice on this as an option.

If you do read this, I am now some what questioning the stud walling with regards in the past properties I have lived in when the walls have had mould and problems you can see straight away and repaint with anti mould paint, dehumidify, wipe and clean of mould but is you stud wall will you a risk trapping problems behind in the first instance or at a later date get problems within the void or with the solid wall behind which are undiscovered?

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