Insulating Solid walls

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Grimly Curmudgeon wrote:

I don't know what building youre referring to, but it seems fairly evident that in the many number of cases of damp near the base of walls, those things listed are routinely factors.
Re rainsplash, it would be a rare building that had such a large roof overhang as to prevent any rain hitting the ground by the base of the exterior walls.
NT
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snipped-for-privacy@care2.com wrote:

But it's a strange one that doesn't have a rood that stops the interior walls getting splashed.

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We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember snipped-for-privacy@care2.com saying something like:

Certainly, they are, and in the vast majority of cases would be the cause. However, this particular wall was facing east, the prevailing weather was from the west and the western-facing wall showed no sign of RD. Or any other form of damp for that matter.

Planters' bungalows, Bwana?
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Dear Dave It is not clear to me for certain, but it appears that you are disagreeing with the assertion that rising damp exists and that you think that no treatment is needed and are citing Geoff Howell as an appropriately qualified, experienced source of unbiased opinon based on good science and statistics. If so, I beg to differ. I do not share Geoff Howell's opinion on rising damp and what it appears that he is claiming. Where is he is right is that many, if not most, dpcs recommended to be put in by unqualifired firms are not needed. Where I think he is wrong and biased is his apparent assertion that rising damp does not exist. He managed to get a substantial grant to research RD at, I think, the University of the South Bank (the old building Poly) which was in many parts a repeat of the work done decades before by the BRE to which anonther post has referred. I will reply to that post as to why I think the BRE work did not work but that is only my opinion! I have surveyed houses for considerably longer than Geoff and have more academic qualifications in more fields - general biochemistry as first degree and specific timber biodegradation as PhD and an Masters in timber engineering. I also have taken and passed with credit in all three modules the CSRT. Geoff has as far as I know a BSc and I understand he is a qualified bricklayer as well but may be wrong. What I do know is that none of the colleagues I have worked with in universities or in the BWPDA or BRE agreee with his theses and I have yet to see a learned paper from a peer reveiewed scientific journal with evidence to support his views. I have seen rising damp in many hundreds of houses
If I were to guess how many houses are needing treatment versus the ones actually treated I would think that it is a minority as Geoff is quite right that lots and lots of treatment is done which is quite unnecessary
Chris
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[snip]

Dear Chris, I note from your company's website, http://www.atics.co.uk/ , that you are mainly concerned with timber decay, wet and dry rot. You give extensive data and information on timber problems and treatments and only THREE SENTENCES regarding 'rising damp'. One sentence tells us to see a link all about fungal decay in wood. Very helpful. The other two sentences tell us what rising damp is, and what you will do about it.
As you give so much technical detail about timber problems why don't you do the same for 'rising damp'? Why don't you show how you prove that the dampness is coming from the ground ? Why don't you describe the test gear/equipment you use ? Where are the details about various bricks, mortars, cements etc.? Where are the graphs showing how damp rises up walls ? I'm sure clients would be reassured and impressed to see similar details as you provide for timber treatments.
I do hope you drilled out a sample of brick and did a chemical analysis of the water/salt content and not just poke an electrical resistance meter at the walls of these ' many hundreds of houses '.
As you are based in London you must have heard about Lewisham Council offering a cash prize a few years ago to anyone who could demonstrate a case of rising damp to them. I believe the man involved at the time was Mike Parrett. I hope you claimed your prize.
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How very interstingly *direct* your questions are... It would appear I may have stumbled unwittingly on a raw nerve...
Here are the answers to your questions
Dear Chris, I note from your company's website, http://www.atics.co.uk/ , that you are mainly concerned with timber decay, wet and dry rot. You give extensive data and information on timber problems and treatments and only THREE SENTENCES regarding 'rising damp'. One sentence tells us to see a link all about fungal decay in wood. Very helpful. The other two sentences tell us what rising damp is, and what you will do about it.
As you give so much technical detail about timber problems why don't you do the same for 'rising damp'? Answer: Because after we did our first two rising damp jobs in 1978/9 as contractor, it became clear to me that there was no money in being a damp-proofing contractor if you were to provide a completely honest unbiased survey service as the cost of a decent survey was about the same as the cost of treatment and that was not fair on our clients. We simply stopped being a damp-proof installer.
Why don't you show how you prove that the dampness is coming from the ground ? Answer :Why shoudl we? I / We have not proved the dampness came out of the ground. We have made no such claim. I have merely read the literature extenisvely, talked to the chaps at BRE or ex-BRE who are recognised as being scientists and have worked in the field and, more importantly, kept a keen eye out on the several thousand houses I have surveyed from Craigievar (sp?) caslte in Aberdeen to Osborne House's Swiss Cottage in the Isle of Wight. I have observed not dampness coming "out of the ground" but dampness coming out of a wall plaster or in mortar as a result of hygroscopic salt contamination. The presence and quantity of such salts are very easiy "proven" by well- established tests that one does for "O" level or GCSE - it does not take a degree to identify them and prove presence. I have done such tests and proved the presence of such salts
Why don't you describe the test gear/equipment you use ? Answer: Because I do not need to for sales purposes on our website. Why would the client be interested in our Speed meter, our Sovereing capacitance meters (3No) and various resistance meters? Why would he/ she be interested in paying a four figure sum of a proper BRE 245 test?
Where are the details about various bricks, mortars, cements etc.? Answer: What aobut them? We are providing a service rather than a Wiki - we provide information on or service. If however, a client makes contact they get a full hard copy of what literature we consider is suitable for their enquiry. Our call - our choice.
Where are the graphs showing how damp rises up walls ? Answer: Why should we show such graphs? Such data are in the public domain.
I'm sure clients would be reassured and impressed to see similar details as you provide for timber treatments. Answer: As we do not offer and have not offered a rising damp *treatment* service as contractors since at least 1980, we see no reason so to do. We do, however, offer an expert opinon service and have, indeed, done the BRE test for hygrosopic salts and free water (Digest 245) using samples from drillings and equilibrating at RH 85% and they oven- dry weight
I do hope you drilled out a sample of brick and did a chemical analysis of the water/salt content and not just poke an electrical resistance meter at the walls of these ' many hundreds of houses '.
Emphatically not - why should I waste the client's money on proving something that any surveyor with experience and a brain sufficiently open to interpret what he sees and the results of meter assessments in the *distribution* of water in a wall combined with where necessary simple salt tests? Only where there is litigation is is necessary to use a ~Speedy meter as that is proof rather than opinion
As you are based in London you must have heard about Lewisham Council offering a cash prize a few years ago to anyone who could demonstrate a case of rising damp to them. I believe the man involved at the time was Mike Parrett. I am well aware of this but - as I say - we do not act as contractors and I will add that we stopped doing "Council" work pretty early on as they were such slow payers and tried to impose "their" rates on us. Most, when they heard that we charged for surveys, were simply not interested. It is only when they get into serious litigation problems that they tend to wake up and pay the man what he is worth.
I hope you claimed your prize.
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snipped-for-privacy@atics.co.uk wrote:
message

snip
No, you - why didn't you claim the prize?!
Rob
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Rob wrote:

How much was the cash prise, and what would be the cost of proving to an adequate level that one deserved it. If the latter exceeded the former, then you have your answer!
--
Cheers,

John.

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John Rumm wrote:

'If' indeed, granted :-)
I'd have thought there must have been a survey done somewhere that demonstrated rising damp beyond doubt.
Rob
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My dad told me that Portsmouth Council had to demolish a huge estate because of rising damp - it was built on the spring line on the side of Portsdown Hill which is made of chalk.
[g]
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The Natural Philosopher wrote:

dry
and
I'm very interested in this at the moment, as the Irish government (which has some Green Party ministers in it) has set out a scheme of insulation grants which includes wall-insulation. In fact due to a bizarre bureaucratic quirk, you more or less have to do treat the walls to get the grant, which also covers attic insulation, but not by itself.
I own an early victorian cottage. A supposed expert told me some time ago that about 35% of the heat is lost through the walls, and only 15% through the ceiling. He didn't do any kind of measurement; this was supposedly the general situation. I wasn't really convinced, but now am thinking of getting some kind of wall insulation. I'm a little worried that this might disimprove the look of the interior, which was very nicely finished by a trawler-owner many years ago for his mistress.
--
Timothy Murphy
e-mail: gayleard /at/ eircom.net
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Dear Tim I suspect we have corresponded before. You have a namesake that is an engineer that used to work with Stephen . I graduated from Trinity in '69 and regularly go back for DUBC occassions still pulling an oar and keeping in touch! Happy to advise you pro bono on any such property and have considerable expertise (that is practical experience) of internal insulation. Is the house in ~Dublin or beyond the pale (as one might say in the old days) Wicklow is great and good for a commute! let me know off line and I can help Chris
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     snipped-for-privacy@care2.com writes:

Outside also means the building's thermal mass is indoors. IME, having a large thermal mass inside the insulation layer leads to a much more comfortable building environment, including staying cooler in summer. Most modern highly insulated buildings have virtually no thermal mass, which is why they're so uncomfortable in hot summers, when there's nothing to stop their temperatures rocketing up.
Unfortunately putting it on the outside is usually impractical.
--
Andrew Gabriel
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Can you enlarge on any vapour barrier issue with regard to external insulation?
My Architect has shown about 75mm of Celotex inside a 220mm single block wall (new build). When I whinged about wall fixing issues he said *stick it on the outside then*.
In fact, this would suit me very well as the external finish is feather edge board on battens. Provided I can find long enough batten fixings, of course.
Does this method give rise to other problems?
regards

--
Tim Lamb

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Tim Lamb wrote:

Mmm. Potentially, yes. And some advantages.
The downside is that any water that gets trapped behind the celotex has only one way to go. Inside the house. Makes the injection even more critical. That means you HAVE to create a really good water barrier outside the celotex..
Conversely you have a lot of thermal mass inside the insulation which is excellent in summer, as it will moderate the hottest part of the day down. Conversely, in winter, it ,means you need to run heating earlier to get up to temperature (if timing).
With a timer cald outside though, its not a bad way to go. Replace vertical battens by maybe 2x2 pressure treated, celotex between, and foil tape the lot before re-boarding.
Pay attention to window and door openings: I'd be inclined to use expanding foam to seal any gaps between celotex and the masonry, and board over afterwards

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er.. This is new build. I was intending to tape the Celotex joints and use a breathable building paper over the battens.

Medium density 220mm block.

Ah! There's the rub. With 4" or so of insulation and battens, there wont be much to fix the window frames.
regards
--
Tim Lamb

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Tim Lamb wrote:

Blimey. I assumed some victorian barn conversion!
Should work. Im a bit leery about battening over and through the celotex..but there is no reason it shouldnt work. I would be more inclined to use exterior timber screwed to the block, mount a slab against it, and then another stud and so on. Then batten over that nailing to the stud. Breathable paper in useful to stop rain driving in past the weatherboarding and getting to the battens, or battens and studs.
Definitely last bit of woodwork should be vertical with an airgap to the celotex to allow air behind the boarding. That should vent near the DPC and at eave level.
I must say if you atrer wood cladding ousisde, i wonder why you ise block at all..use a timber frame, plate in ply, then paper and battens and weatherboard, and stick the celottex inside between the studs..
Thats what I have. More or less. Cavity brick up to about a foot off the ground, with a DPC.batts inside, then sole plates and studowork above. Outside is rendered over wire rather than boarderd., otherwise its the same.

Not a problem really. Build a softwood treated frame outside the blockwork there.
Piece of piss to screw that to the block and attach windows to it. You can run the boarding over the top of that, and if the window is left a bit proud, up to the edge of the window. I.e. dont fit the windows till its all boarded up. Then a bit of mastic will seal 'er up nice.
Its a bit of a cold bridge, but life is never perfect..so is the window frame anyway!
Then line the alcove with plasterboard. and a nice window board. And maybe tidy up outside with a drip board and some lead run under the board above and over the drip board top.

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Do keep up:-) The Victorian barn is currently having some underpinning/structural pads installed so I can put a steel frame inside. Unfortunately it forms two sides of some new build for which I am struggling to find affordable builders. I think I have got a handle on this now: interstud insulation, plywood exterior and then more Celotex and new block.

Yes. Not Mouse size vents though! I could use eaves vent or rely on warping from the feather edge.

You are not inches from a busy by-way. I'll start in cavity brick and break to 220mm block + insulation behind the boarding.
regards

--
Tim Lamb

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I don't claim any particular expertise here, but a vapour barrier is used to prevent warm moist indoor air migrating to a cold surface where condensation will form. If you have external insulation and it is moisture-proof such as foiled celotex/kingspan, then there isn't going to be any place where condensation can form. However, in practice, it's unlikely that the celotex/kingspan is going to be your only insulation layer. For example, if your inner skin is thermal blocks, then they will also contribute to the insulation, and the junction between the block and Celotex will be colder than indoors, and there's scope for condensation there. My guess is that is not likely to be enough colder to be below the dew point and plastered walls won't be sufficiently moisture permiable, but I would seek some expert advice here, and there are probably applicable building regs.
The other thing is that thermal blocks don't have a lot of thermal mass anyway (compared with bricks or clinker/breeze blocks). I was thinking rather more of victorian houses with brick walls when I made the comment about external insulation. It's worth thinking about for a newbuild, and I share your dislike of drylined walls. If you can get non-thermal blocks (with higher thermal mass) cheaper, possibly in exchange for another 25mm of celotex, that might be a good idea.
--
Andrew Gabriel
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Medium density block is specified.

OK
OK again. I suppose foil backed dot and dab plaster board is likely to impede moist air transition.
regards

--
Tim Lamb

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