Looking for someone who specialises in insulating old houses

Tusky

Howdy folks,

My house is 100 years old and single brick construction. Every tradesman I've asked has suggested fixing insulated plasterboard directly to the wall. I know this method can cause condensation issues, but none of them seemed to be aware when I raised it with them.

Can anyone put me in touch with someone with experience of the various systems that can be used to insulated these old houses?

If you're gonna name a person or company please PM me rather than posting publicly.

Thanks!

Ginger83

https://www.kore-system.com/blog/transforming-a-derelict-house-into-a-low-energy-gem-with-kore-deep-retrofit

Read this.

Tusky

Ginger83 wrote: »

https://www.kore-system.com/blog/transforming-a-derelict-house-into-a-low-energy-gem-with-kore-deep-retrofit

Read this.

That looks fantastic but waaaaay out of my budget. I probably shouldn't have said specialised. I'm just looking for someone who is familiar with some of the methods used to insulate old houses.

Lumen

Irish Georgian Society have a skills register
https://igs.ie/conservation/list/register/category/dublin

You might try googling for companies bragging about using certain products e.g. calsitherm climate board site:ie

Or speak to one of the suppliers of these conversation products and get names of companies that are buying a lot of it.

BryanF

Tusky wrote: »

That looks fantastic but waaaaay out of my budget. I probably shouldn't have said specialised. I'm just looking for someone who is familiar with some of the methods used to insulate old houses.

External wall insulation is probably the way to go.
As regards walls Research:
Hemp-lime
Cork-lime
Calcium silicate
Gutex

booooonzo

What is the external render on your house at present?

IQ Therm is another one you can add to your list. Note: i have zero experience with using it, just I have been doing similar looking as yourself and finding it very hard to find someone who can give concrete (excuse the pun) advice.

there is a lad -snip-. again not a recommendation, expect to pay about 800quid for it if it suited you.

Let me know how you get on, would be interested to know as we are still no further on.

Fann Linn

SEAI have a full list of contractors.

Tusky

BryanF wrote: »

External wall insulation is probably the way to go.
As regards walls Research:
Hemp-lime
Cork-lime
Calcium silicate
Gutex

External wall insulation is not possible unfortunately, so I have to find an internal solution. Thanks for the options. Can you point me in the direction of someone who can install them?

booooonzo wrote: »

What is the external render on your house at present?

IQ Therm is another one you can add to your list. Note: i have zero experience with using it, just I have been doing similar looking as yourself and finding it very hard to find someone who can give concrete (excuse the pun) advice.

there is a lad -snip-. again not a recommendation, expect to pay about 800quid for it if it suited you.

Let me know how you get on, would be interested to know as we are still no further on.

I'll PM you now as the person has been edited from your post.

It's pointed brick on the outside. I've had three plasterers and one builder tell me to bolt 50mm insulated plasterboard directly to the bricks using mushroom fixings. At this stage I'm tempted to do it because it's the cheapest and best insulation. If it causes problems down the line I can always rip it out and find an alternative. But at the moment I'm finding it very hard to find someone who installs any of the alternative options.

antiskeptic

Tusky wrote: »

It's pointed brick on the outside. I've had three plasterers and one builder tell me to bolt 50mm insulated plasterboard directly to the bricks using mushroom fixings. At this stage I'm tempted to do it because it's the cheapest and best insulation. If it causes problems down the line I can always rip it out and find an alternative. But at the moment I'm finding it very hard to find someone who installs any of the alternative options.

Bolting directly to the bricks means the board will follow the shape of the wall and the skim will follow the shape of the board. If the wall is wavy the finish will be wavy. Bad advice thus. A "proper" builder would dab and slab - levelling out each board and making sure the end result was a perfectly flat plane. Or he'd set out the battens with spacers compensating for dips and hollows to give a level plane to attach boards to.

You won't know there's mould problems down the line because the problems will be hidden behind the plasterboard. Spores, if developing behind the board, will migrate into the house. You won't necessarily see mould on the surface of board.

-

The mould problem, to my eye, appears to lie with the lack of ventilation between rear of warmboard and inner surface of wall - if the boards are installed per usual methods. Damp drives through the wall, has nowhere to go and mould develops.

But what if you take steps to resolve that problem?

Let's suppose the wall is battened out vertically - but you cut a number of small sections out of each vertical batten which will, when finished, allow air movement between vertical portions of the battened out wall. It would take more careful battening and more fixings but it's not complicated. Or you could drill a decent number of holes sideways through the battens, preserving their structural integrity. It wouldn't take long.

You ensure you have perimeter battening on each wall: top/side/bottom to act as a fire/air break. You could, if you fancy it, apply a bead of foam to the perimeter battening during slab installation to improve air tightness.

To finish you install brick-size ventilation holes - say 2 bottom/2 top per wall (inside the perimeter battening). You can find nice period brick sized ventilation inserts in either brick or cast iron for this job.

Effect: you have an air gap between the back of the board and the wall. And you are ventilating that space without air being able to get into the house. Any moisture driving through the wall will be vented away, preventing mould development. And you're gaining air tightness (seal the perimeter where floorboards meet wall too)

Heck, if you really wanted to go to town you could put a couple of fans in there which are moisture level activated .

I don't see why you couldn't keep it simple and use dab and slab instead of battens to achieve the same thing - if the wall is kept dry by virtue of ventilation, there ought be no issue with adhesive adhesion breaking down due to damp conditions.




ps: if going through the trouble, I wouldn't bother with 50mm boards. Get something meaty in there that will make the place snug and warm.

Lumen

^^ that sounds like much more work than just using vapour permeable insulation boards, lime plaster and clay paint.

antiskeptic

Lumen wrote: »

^^ that sounds like much more work than just using vapour permeable insulation boards, lime plaster and clay paint.

If simple dab and slab, you're only adding 4 vents per wall on top of the job. A couple of hours per wall?

If holes in standard battening? An hour on top of the few hours for vent work?

The breathable stuff is far more expensive - and you have to remove whatever's on the wall first iirc.

And you can only go up limited thickness (50mm or so?)

No contest.

Lumen

antiskeptic wrote: »

you have to remove whatever's on the wall first iirc.

That's an interesting point. I'm not so sure in this case. It's obvs not ideal but the brick would breathe to the outside and the insulation would breathe to the inside - I guess you'd still get condensation if the RH was high enough but the insulation might wick it back from the original plaster.

antiskeptic wrote: »

And you can only go up limited thickness (50mm or so?)

Wool boards and Calsitherm are quite thin (<60mm) but Pavatex do a room-side product called Pavadentro that goes up to 100mm and can be directly plastered (I think).

antiskeptic

Lumen wrote: »

That's an interesting point. I'm not so sure in this case. It's obvs not ideal but the brick would breathe to the outside and the insulation would breathe to the inside - I guess you'd still get condensation if the RH was high enough but the insulation might wick it back from the original plaster.

I can't remember the technicalities but would myself have thought the brick+orig plaster+new breathable insulation as one entity. The original wall, when wet would simply evaporate to both sides. Nothing different if adding a breathable layer to the interior. But I do recall the chap saying the old plaster had to off.

And I remember the price causing immediate rejection of the option of breathable.

Wool boards and Calsitherm are quite thin (<60mm) but Pavatex do a room-side product called Pavadentro that goes up to 100mm and can be directly plastered (I think).

The question is: is there anything particularly wrong with what I suggest. Bog standard practices (read: the cheapest of possible chips) ... with a twist. If nothing wrong then it would be the way to go.

I don't work for Xtratherm btw.

BryanF

antiskeptic wrote: »

The question is: is there anything particularly wrong with what I suggest. Bog standard practices (read: the cheapest of possible chips) ... with a twist. If nothing wrong then it would be the way to go..

Yes. Your inviting moisture & air into a cavity created with non continuous insulation /air-tightness.

antiskeptic

BryanF wrote: »

Yes. Your inviting moisture & air into a cavity created with non continuous insulation /air-tightness.

The idea is to compare with an expensive alternative: internal breathable, rather than a modern build ideal.

Air (and the moisture in it) is indeed invited into the cavity - for the same reason air and the moisture in it are invited into the cavity between suspended timber floor and muck. That in itself isn't a bad thing.

The cavity can be made airtight using a continuous bead of perimeter adhesive. The context is a 100 year old building where ventilation is going to be required anyway.

The insulation isn't continuous - there's adhesive around the perimeter. That said, the insulation in the alternative isn't continuous either - it's typically coming up against internal walls, floors and ceilings (unless part of a complete gut and refurbish job)

st1979

What about hempcrete or lime hemp. I am in the middle of doing a room up in a stone built house and am having similar questions to the op. My Walls are 500mm thick. Been looking at various ways. A lot of the ways are very expensive to my eyes. The lime systems seems to be a slower process though. Due to drying times. The other option is the wood fibre boards.
Would think I could do the hemp plastering myself. And am no longer in a rush to be finished for Christmas which has encouraged me to use lime.

Lumen

I quite like the idea of internal wood cladding over woodfibre. Would mean no wet trades and easy DIY. Although finishing around windows might be fiddly.

antiskeptic

Lumen wrote: »

I quite like the idea of internal wood cladding over woodfibre. Would mean no wet trades and easy DIY. Although finishing around windows might be fiddly.

My guess would be that woodfibre isn't suitable for use where a wall is physically damp/wet - such as might be expected to occur with a single leaf brick wall.

Water as gas passing through wood fibre is one thing, damp/wet & woodfibre in the same vicinity, quite another.

Calahonda52

antiskeptic wrote: »

My guess would be that woodfibre isn't suitable for use where a wall is physically damp/wet - such as might be expected to occur with a single leaf brick wall.

Water as gas passing through wood fibre is one thing, damp/wet & woodfibre in the same vicinity, quite another.

IFF the wall is lime based,and the construction fully breathable, then the WF can absorb moisture as wet, up to IIRC 2.5 litres/m3

antiskeptic

Calahonda52 wrote: »

IFF the wall is lime based,and the construction fully breathable, then the WF can absorb moisture as wet, up to IIRC 2.5 litres/m3

Wow!

Lumen

Calahonda52 wrote: »

IFF the wall is lime based,and the construction fully breathable, then the WF can absorb moisture as wet, up to IIRC 2.5 litres/m3

Can you remember where you got this information from?

I had a conversation today with someone who specifies breathable wall systems, and he explained that wood fibre is not good for dealing with liquid water. It doesn't wick, it just sits on the surface.

Calsitherm, on the other hand, sucks it up and disperses it incredibly well.

I saw this demonstrated using an upturned glass of water. Very interesting.