more conflicting advice about lime, etc, sob.

[tycarregydwr]

All fired up from my readings about lime and looking forward to speaking to conservation builders and lime specialists, I was happily convinced that the 'right' thing to do, in the ideal circumstances, for the health of our house would be to strip the cement pebbledash from the outside, strip the cement render and plaster from inside, and lime it all over. I don't know if we can afford this but it seemed unequivocal that this was the 'proper' thing to do, and the books I am reading very confidently assured me that this would make my walls breathable and dry and my house warm.

A chap has just been to talk wood burners. He comes very highly recommended, including recommendations from someone with a beautifully preserved old house, and several eco-energy people. He said that he's seen many old solid wall houses in this area completely de-cemented and re-limed inside and out, and that they are still horrid and damp, with walls that are still cold and therefore mouldy. He said on his own house he has removed the cement and re-limed the exterior, but on the inside left all the cement and installed insulated, moisture-proof plasterboard over it, this way the inside wall is warm and dry, and any moisture in the wall evaporates to the outside. (He also said that he would suggest drilling a small hole directly through the solid wall for a vent pipe to feed the stove, this worries me as it's a rubble-core and I don't want to make holes in it!)

I want a warm, dry house (within reason, I do not expect a balmy 72 degrees or anything, I just want to avoid lots of black mould and freezing to death in my bed), but every single person I speak to has a wildly different suggestion on how to achieve this.

Sorry for the hysteria. I assume no one on here has de-cemented and re-limed a house and been really unhappy about it?

 

[Baron de Gynes]

With reference to the woodburner vent pipe; there should be sufficient air draught for the burner to work a) effectively and b) safely. Without sufficient ventilation to a solid-fuel applience there are very real dangers of Carbon Monoxide poisoning. That's most likely his rationale for the installation of a vent (that, and it may be a requirement rather than an advisory suggestion).

As for the breathability of walls encased with lime on both sides or on only one, I cannot comment but I would be willing to bet there will be someone else along in a moment who will be far more effusive on the subject! :lol:

It does get pretty wet up in the wilds of Wales though...

 

[skier-hughes]

Our 40kw fire with backboiler has an outside air inlet, whereas our 2kw one in my wifes office just uses the air from the room.
Some fires will need one, some won't, from my research previously the bigger the fire the more likely it is to need an outside inlet!

Why are the houses he's seen horrid and damp? Is the horrid due to being cold? If so, he obviously didn't install the right size fire for the circumstances. If they are damp, have they done other remdial work, like roofs, drainage, ground levels, attaching lime to your walls is not a fix all solution and won't make your house warm, but it'll be part of a proper works schedule!

Our house was cold, we had a raybrun firing 19 large rads when it was designed for 8 small. With our new heating system we can have a totally warm house if we want to, which is lovely. I also know where the damp is, and what I need to do to rectfy it. Previously I didn't know and thus wouldn't have done any works!!!!

 

[JohnB]

I'm taking the cement off inside and out. I don't know how just taking it off outside would work as far as drying out the walls is concerned, but I've got some rotted beams and lintels where they have been sealed in with cement and gypsum plaster inside. So the inside is coming off to deal with that.

 

[tycarregydwr]

I know a vent is needed as per regs for the size burner we want, it's just how he proposed doing it that I found slightly disconcerting. A previous installer had said he could make a hole in the wall at the other end of the room (modern cavity extension).

He said the other houses he's seen, full-on restoration jobs from what I could gather, had walls that were cold and had cold, damp corners. I don't even know if these were ones he'd fitted stoves in but he is the most highly-recommended guy in the area so I really do have confidence in his knowledge on the stove and heat issue. But obviously that doesn't qualify him to have expert opinions on the lime debate. I was just taken aback, given that he's clearly got *some* clue - he's not saying lime is bad, he's not an ill-informed modern builder suggesting injection damp-proofing or anything like that - and with experience on restorations and eco-new builds, and he's saying lime isn't the best solution.

I don't want to argue, nor am I trying to be devil's advocate, I promise! And I do apologise for the hysteria but this is all so confusing and just as soon as I start to think I've begun to understand, BHAM, I am again clueless.

 

[Andrew Bodenham]

tycarregydwr,

As with many 'old house' projects there are so many ways that one might proceed; it really is difficult to know what will produce an optimum result within a realistic budget. Advice from individuals who are not building specialists tends to be anecdotal, and whilst personal experiences can be enlightening they do not always convey the complexity of a particular situation. So many variables are involved in producing 'a warm, dry house' that simply isolating one e.g. the use of lime plaster internally, and saying that such-and-such a house was lime plastered but still damp, is a hopeless over-simplification. Wall construction and materials, location and topography, orientation and exposure, patterns of occupancy, type and use of heating systems, provision for ventilation, surface finishes, glazing, insulation - or lack of..... all these factors and many more have an effect on the attainment of 'warm and dry'.

However, reading around the subject and talking to experts, one encounters recurring themes. The need for the outer skin to be vapour permenable, so that water that gets in can also get out. The need to address gross defects such as leaking gutters, high external ground levels or defective pointing. And the need for heating and ventilation.

I'm currently fitting some new windows to my house, and hacking out bits of cement pointing which I did almost 15 years ago, before I knew better. It's noticable that the bedding mortar behind the cement is wet, even during a dry spell, which is enough of an incentive for me to want to remove it and replace with lime-based pointing. Having a vapour-permeable outer skin is a goal worth pursuing.

In some rooms the old lime plaster has been replaced with cement render and gypsum plaster ( forgive me, Lord, I knew not what I did....) and these rooms are warm and dry - but that's due to heat and ventilation. The remaining lime plastered rooms are equally warm and dry. I am adding insulated board linings to the window reveals because we've had mould problems at these cold-bridge areas. But other areas are being left without insulation. Double glazing helps with keeping the place warm, but do these new draught-sealed windows help with ventilation? I'm seriously thinking about heat-recovery ventilation for the whole house.

To conclude: listen to all the anecdotes, read all the books, talk to experts, see other similar properties, but vitally try to understand the principles which underly decisions about which materials to use, and keep an overview of how one particular element will affect others in the bigger picture.

PS: I've also just installed an externally-vented woodburner. This method of installation makes so much sense, compared to having an air vent somewhere in the room and hoping that air will find its way to the stove - and having a roaring cold draught on a windy day. All the ventilation and other requirments are given in DocJ of the building regs which can be downloaded free from the Planning Portal site. I started drilling the 1000mm long hole for the vent duct through our rubble-core walls, and as usual with these things ended up making a much bigger hole, installing the duct and then building back around it. It's not as straightforward as putting a neat 150mm hole thorough brickwork with a diamond core-bit, but it's certainly possible with a little effort.

 

[tycarregydwr]

Andrew, thank you, especially for the PS! He was indeed suggesting what you describe, although I think our preferred model of stove does not have this option, but he said this is what he now recommends as a best option.

Everything else you say are helpful, soothing words too. I know that 'the plural of anecdote isn't evidence' as a friend of mine says. It is just so much to take in. Well one thing is for sure, with so much information to acquire and assimilate, we definitely won't be making any hasty decisions about how to proceed!

 

[plasticpigeon]

I'm having similar thoughts to you particularly regarding plaster. I'm convinced of the benefit of lime on the outside of the house as I've seen the damage caused by cement pointing. It also makes sense to me that an impermeable coating such as cement render but also paint on the outside will tend to trap water between it and the masonry if water gets in, which is particularly bad if it freezes. Cement also causes much damage when it comes off.

I'm not convinced that the inside wall coverings are so important. I've taken off cement inside a kitchen and it's been dry underneath and I have a damp section of wall that is lime plastered one side and bare brick the other. That particular wall is an internal wall but with no damp proof course. That bit of damp perplexes me as I'm not convinced the damp is rising as the bricks below the floorboards seem dry, but it shows that lime is not magical!!! I don't care for plasterboard on walls and for a novice like me lime is probably easier to apply as it takes longer to set, so I shall use lime. It also means I can come on this forum with impunity even though deep down I think other alternatives would probably be ok!!!! (PVAing a wall and bonding is too much for me to stomach though)

 

[skier-hughes]

Lime is not a cure for damp, it purely lets water from the brickwork pass through. If there is very little moisture this passing through will lead to dryness, but if there is lots of moisture damp will be there. At least you know it is there and probably not as bad as it could be if you had a non permeable covering.

When we had our air duct installed I told the fitters exactly where I wanted it and why. They understood my reasoning and I paid for the extra work involved in routing it that way. I wouldn't employ a contractor who either wouldn't follow my instructions or give me such good advice and reasoning for why it should be done differently to my way. Cost wouldn't be a good reason for taking short cuts in my book.

 

[middi]

Regarding woodburners and air inlets , yes there are regulations ( anything above 5 kw requires an appropriate external vent - I think)
This regulation can easily be checked.
What you cannot check with regulation, or regulated by it, is where this ( adequately regulated) vent has to be fitted within the room or building.
The external vent ( as required by the fire updraught, " draw") to operate correctly needs to be as close to the fire as possible. Immediately in front or to it's side is ideal. anywhere else within the room ( especially on an opposing side wall) will create a cold draught across the room.

As to condensation, damp, etc.. there are as many buildings as there are ways to cure it.

Middi

 

[BillH]

Hello,

we live in a timber frame.

we had lime on all of our inside walls, and cement on the exterior, we had severe rotting on some of the timbers on the front , and went for repairing all the damaged timbers and replacing all the cement with lime render . The back is rendered in lime but there are no timbers showing, so I am hoping that the timbers are protected from all exterior damp by the external cement render. The internal are lime so they can breath all be it one way :?

In our house we had a very narrow gap between the internal and external walls , we put in sheeps wool in an efort to insulate a little, about one inch.


our only problem since doing this job three years ago, has been where the timber has shrunk (one area) and we have had to re render a second time, builders cost. Just make sure your timber has been dried very well, it might cost a little extra, but on the whole front of the house the first two thirds was fine, but the last but shrunk a little creating a gap in the render.. same with the lathes.. we had a different batch at the end which may of made a difference..


is it hotter or cooler because we are using lime ? no different really.

we need to keep the central heating on , or the log burner burning..

I think it is incredibly comfortable in summer, we suffer a little in winter as the external doors are not air tight. The wiindows are thin single glass with some air gaps here and there , so the house is a bit leaky.. hard , nay impossible to insulate
The lobby has no heating at all.
Just revamped the central heating with an additional pump. I think that will improve the overall heating.

is it dry ? yes bone dry there are two skins, the outside one might get wet, but the internal one doesn't..


is it worth it ? it's an expensive process,but actually it is a must do, certainly in our case, or they could of been serious problems down the line. Half had to be done now now now , and the other half shortly , say 5 years..
In saying that , the oak is resilient.. we had one corner post 9 x9 inches, hollowed out by worm due to the wet, and the experts ummed and arred should we or should we not take it out and replace it...Well I didn't want to revisit the question in five years time so we had it out..
We had a 3 - 4 m sole plate that looked old and solid, but when we took it out, crumbled to dust.. The other sole plate similar issue, but had collapsed causing a problem further up the house , while it had all held together , it had caused strain, just not good.

there are some man made products (like plaster board) that can be used as an insulation , instead of the sheeps wool and then plastered onto, the agony uncle may know the names.. all depends on the gap between the two skins.


There is some new timber in the house frame, but it weathers in, Everytime I look at the place I think , thats good for the next 500 years ! on the other hand if you are 90 years of age, no kids, and your life expectancy is somewhat shorter, go to monte carlo and stick it all on black !

long and short, if you have the money, IMHO do the job, if you dont, you will never be able to fund your doteage by selling the place if its falling apart .. a stitch in time etc.. rgds bill

 

[Keithj]

Greetings!

We had a house half way up a mountain on the Lleyn Peninsula. it was cold and damp when we bought it, and warm and snug ten years later when we sold it.
That was due entirely to the brilliant efforts of one man, Griff Jones, who knows more about houses on mountainsides than you would think possible. He told us such news as: rain goes uphill on a mountainside - think about it: a strong wind blowing onto the mountain, with a gentle rain falling. Of course the rain goes upwards. Hence, a six-inch overhang with the slates won't keep the wet out. It needs to be 18 inches. And so on, and on.

We worked steadily round the house, starting with the dampest bits, until it was all done and snug dry and warm. The house was stone (granite, mostly) built almost like drystone walling with mud in the gaps. Hence, he could use cement (and did). We tried heating it with logs, coal, anything we could get hold of. That didn't work. Oil was the answer - a good, healthy boiler down in the cellar, breathing and venting via the downhill wall so there were no draughts. The clever heating man (from Caernarfon) managed to hook the oil boiler in the basement to the pipework previously fed from the back boiler in the lounge. The back boiler was, of course, totally inadequate for the job.

We are now in a Tudor house with a timber frame. That's a totally different story: cement is a no-no where oak is concerned. We've spent a bit over £30k removing concrete (plastered onto the house about 15 years ago), and replacing 15th century timbers rotted by concrete and age. All is now lime rendered. In my (simple) book, if you have a timber frame, concrete is a very bad idea and lime is the only way.

Our heating is oil-fired. The boiler is in the utility room, mounted on an outside wall and drawing its air through the wall. That is the best way to go, given a choice.

We have open fires in the two lounges, and they are a delight on a winter's night - but I wouldn't be without the oil system.