Solid Wall Insulation

[bighouseproblems]

So I am up to my neck in various form of insulation. Hours upon hours of reaserching but here we go. 

 

Solid Sandstone Walls on the front of my house. Solid Bricks on the rear after a rebuild well before my time.

I have got to the point of these options.

Some idiot years ago ripped out all the lime plaster and metal framed and plasterboarded the whole house. My wish given an endless pot of money would be to reinstall lime plaster.

 

Option 1

Solid wall(Sandstone)

20-30mm void not vented but may look at venting into the loft space.

2x6 stud filled with 140mm possibly rockwool or frametherm

VCL

2x 12.5mm soundbloc plasterboard

 

This is my favoured approach due to the increased performance of the combined materials however i do have concern about sitting them against each other between the studs

Option 2

Solid Wall

20-30mm void

2x6 studs 90mm Rockwool with 50mm pir ontop of it 

VCL

2x 12.5mm soundbloc

 

Option 3

solid wall

20-30mm void

2x4 studs 90mm rockwool

50mm insulated plasterboard or 50mm pir

12.5mm soundbloc

 

I do have plenty of room in the house so eating into the space is not a great concern but don't want to go to mad.

Keen to have a mineral wool insulation due to its sound absortion properties and also the cost factor.

I am very aware of the issue with insulating solid wall properties and have investigated every option under the sun however sometimes you have to just go with your gut and it has survived so far with gypsum. 

 

has anyone done a similar setup?

 

ps i have run these setups through ubakus and they look ok. 

 

 

[saveasteading]

I am going through the same thought process.

I am returning to my original inclination to not leave an air gap.

Instead to fill that space with waterproof cavity batt. Thus there is no air flow sucking away the condiderable thermal benefit of the stone wall. The external wall can breathe outwards. No possibility of damp (?) And improved insulstion.

[bighouseproblems]

Just read through your very long thread.

 

I personally think that would end up in transferring the moisture elsewhere ie it would sit on the floor or run down the house somehow.

From what i have read you either go fully orignal and lime plaster everything which may or may not give you the desired u values and also may not aid with noise levels (debateable)

or go with a halfway approach of letting the wall breath on the inside and out and treat it as it's own entity and then insulate the inside.

 

I have spent so many house reading eveything i can find and there is no "right" approach as far as i can tell. If i was in your postion and climate factors were plageuing your decisions i would probably take a look into some moisture measuring tools and temperature sensors and start taking measurements of the walls inside and out. Also you could create a mock up section seal it to the wall and then investigate it after a week or 2. 

 

I am going down the suck it and see route as i have a wife and child and i am wrong and it doesnt go well i guess i will have to replace it all.

[nod]

You need to leave a void 

I often gypliner properties 50 mill Rockwool bat for sound and insulation 

15 mil void While The bats will repel water in a cavity There not waterproof 

and any damp on the masonry will strike through 

 

While line plaster can be quite fashionable 

it will act s a sponge if the walls are damp 

Which is probably why the previous owner MF it out 

[Mr Punter]

I think the 100mm stud would be OK.  Can you make these up as timber framed panels and stand them up?  You could even have OSB sheathing and breather paper on the outside to maintain the cavity.

[bighouseproblems]

I will be leaving a void probably 30mm to be safe. Currently there is gypliner installed but is set too close to the wall to then fit any meaningful insulation plus the upright stud are wafer thin I looked into some insulation clips but ultimately thought sod it I'll just take it out and have a wooden stud built up that will take the insulation better. Was thinking of OSB but if they are built on the wall might be a nightmare and possibly breather paper might work on the outside of the insulation closest to the wall you mean?

[bighouseproblems]

Outside wall after a massive amount of rainfall and driving rain today. My hope is it will still dry out and I can monitor it once the insulation is installed.

[SteamyTea]

49 minutes ago, bighouseproblems said:

Outside wall after a massive amount of rainfall and driving rain today

No amount of lime is going to help there.

[bighouseproblems]

4 minutes ago, SteamyTea said:

No amount of lime is going to help there.

Can you see a problem I cannot? The wall has dried out almost immediately it was all soaking wet only a few hours earlier? 

[Adsibob]

Knock the house down and start again. That’s what I often wish I had done with my 1930s semi…

[SteamyTea]

49 minutes ago, bighouseproblems said:

Can you see a problem I cannot?

You got to stop the water getting though, not just thinking that a lime finish will let it dry out faster.

Do you have a gutter/downpipe leaking onto it?

25 minutes ago, Adsibob said:

Knock the house down and start again.

With your builder, there is still time.

[bighouseproblems]

6 minutes ago, SteamyTea said:

You got to stop the water getting though, not just thinking that a lime finish will let it dry out faster.

Do you have a gutter/downpipe leaking onto it?

With your builder, there is still time.

I don't think a lime finish will help anything to be fair. That is an external wall which was covered in some paint which I have started to remove. Plan is remove it back to bare brick and see how it goes. Guttering is ok but was put up quickly when we moved in. Eventually the roof will get completely redone. That's if I don't knock it down before like Bob suggests ha. But all jokes aside I am happy with the building as it stands I have belief it will perform fine once we start upping the insulation inside but you never know. 

[Adsibob]

23 minutes ago, SteamyTea said:

 

With your builder, there is still time.

No, we are seriously moving in within 4-5 weeks.

[SteamyTea]

5 minutes ago, Adsibob said:

No, we are seriously moving in within 4-5 weeks.

It is usual to have a house warming party.

Trash the place as everyone knows a place gets decorated after the move.

[Cpd]

Option 3 would be my choice but if possible I would have a small amount of ventilation in the void, nothing crazy but some sort of airflow to allow any damp to be removed when the wind was blowing. I am thinking that on my renovation I will use 75mm pir between studs and then 50mm over the studs followed by PB. I have no issues with noise as I live in the sticks. 

[SteamyTea]

3 minutes ago, Cpd said:

if possible I would have a small amount of ventilation in the void, nothing crazy but some sort of airflow to allow any damp to be removed when the wind was blowing.

Could you use a Tyvek type material on plastic battens to create a small void, then the mineral wool insulation, then VCL then plasterboard.

If done with care the mineral wool is made windproof, but not vapour proof.

[Cpd]

3 minutes ago, SteamyTea said:

Could you use a Tyvek type material on plastic battens to create a small void, then the mineral wool insulation, then VCL then plasterboard.

If done with care the mineral wool is made windproof, but not vapour proof.

I have often thought this would be a good solution but don’t know of people who have done it. - I don’t think you need the plastic batten just treated wood in a vented void would be fine. 

Edited February 16, 2022 by Cpd

[jayc89]

No support for the "warm batten" method? PIR direct to the wall, taped, batten over fixed with concrete screws to form a service void on the warm side and plasterboard over the battens.

[SteamyTea]

3 minutes ago, Cpd said:

I have often thought this would be a good solution but don’t know of people who have done it. - I don’t think you need the plastic batten just treated wood in a vented void would be fine. 

Someone must have a brick shed to try it out on.

[bighouseproblems]

1 hour ago, Cpd said:

Option 3 would be my choice but if possible I would have a small amount of ventilation in the void, nothing crazy but some sort of airflow to allow any damp to be removed when the wind was blowing. I am thinking that on my renovation I will use 75mm pir between studs and then 50mm over the studs followed by PB. I have no issues with noise as I live in the sticks. 

I had it in my head to have all the insulation in the studs leaving it easier to mount the plaster board to be fair. 

Thought about the warm batten method but something in my head keeps telling me to separate the wall from the inside. I have to admit I'm not overly worried about the sandstone wall on the front as it is South facing and gets quite a bit of sun daily. 

 

Has anyone run two types of insulation together?

[Cpd]

1 minute ago, bighouseproblems said:

Has anyone run two types of insulation together?

Yes…. In another building I have 170mm of rockwool between the roof joists and 70mm if PIR below, seems to work well ! Always put the more breathable insulation to the outside, but on a recent new build I have seen it done back to front…… not sure if this is a good thing.  - I am not an expert by a long shot so don’t take my view as gospel….. 

 

6 minutes ago, bighouseproblems said:

I had it in my head to have all the insulation in the studs leaving it easier to mount the plaster board to be fair. 

If you do this you have repetitive cold bridges at every stud and could cause problems with condensation forming on the cold areas. 

[SimonD]

4 hours ago, bighouseproblems said:

So I am up to my neck in various form of insulation. Hours upon hours of reaserching but here we go. 

 

Solid Sandstone Walls on the front of my house. Solid Bricks on the rear after a rebuild well before my time.

I have got to the point of these options.

Some idiot years ago ripped out all the lime plaster and metal framed and plasterboarded the whole house. My wish given an endless pot of money would be to reinstall lime plaster.

 

Option 1

Solid wall(Sandstone)

20-30mm void not vented but may look at venting into the loft space.

2x6 stud filled with 140mm possibly rockwool or frametherm

VCL

2x 12.5mm soundbloc plasterboard

 

This is my favoured approach due to the increased performance of the combined materials however i do have concern about sitting them against each other between the studs

Option 2

Solid Wall

20-30mm void

2x6 studs 90mm Rockwool with 50mm pir ontop of it 

VCL

2x 12.5mm soundbloc

 

Option 3

solid wall

20-30mm void

2x4 studs 90mm rockwool

50mm insulated plasterboard or 50mm pir

12.5mm soundbloc

 

I do have plenty of room in the house so eating into the space is not a great concern but don't want to go to mad.

Keen to have a mineral wool insulation due to its sound absortion properties and also the cost factor.

I am very aware of the issue with insulating solid wall properties and have investigated every option under the sun however sometimes you have to just go with your gut and it has survived so far with gypsum. 

 

has anyone done a similar setup?

 

ps i have run these setups through ubakus and they look ok. 

 

 

 

Are you doing a whole house retro fit? If so, have you planned for the required ventilation with these buildups? Also, may I ask why you've discounted the use of natural insulation installed directly to the wall? Because this can be breathable, you'll find they'll have an edge when it comes to indoor air quality and feel. It doesn't look like you've got to worry about your walls being too wet.

[bighouseproblems]

2 minutes ago, SimonD said:

 

Are you doing a whole house retro fit? If so, have you planned for the required ventilation with these buildups? Also, may I ask why you've discounted the use of natural insulation installed directly to the wall? Because this can be breathable, you'll find they'll have an edge when it comes to indoor air quality and feel. It doesn't look like you've got to worry about your walls being too wet.

Yeah we have 9 rooms to retrofit, the smallest room apart from the bathroom is probably 4mx4m. The reason for not going natural is for a few reasons 1. Finding people who will do it contacted a few explained never heard back. 2. Cost which would be substantial 3. Noise levels the house is like a bomb shelter but we do have heavy goods vehicles coming past at times and would like it as quiet as possible. 4. Lastly I am starting to think about future proofing the house for solar and ashp with energy rates being what they are. £2,500 energy bill for the last year lol will probably be £5,000 this time next year ha. So in essence it's about coming up with a common sense solution that can be executed over the whole house in a relatively timely manner.

 

. 

[saveasteading]

Bighouseproblems, can we go back a bit. Sandstone front. How thick, how formal/rubble? Any interna lining?

brick rear. Ditto.

 

I will read up on  "warm batten" as this is the first I have heard of it but is what I am thinking of. 

Re earlier question, I am proposing cavity batt as used as full fill insulation, so is not going to absorb any moisture.

From recent reading, a masonry wall with lime mortar is going to breathe outwards. I can't see that encouraging evaporation into a warmish internal void is a good thing.

[bighouseproblems]

9 hours ago, saveasteading said:

Bighouseproblems, can we go back a bit. Sandstone front. How thick, how formal/rubble? Any interna lining?

brick rear. Ditto.

 

I will read up on  "warm batten" as this is the first I have heard of it but is what I am thinking of. 

Re earlier question, I am proposing cavity batt as used as full fill insulation, so is not going to absorb any moisture.

From recent reading, a masonry wall with lime mortar is going to breathe outwards. I can't see that encouraging evaporation into a warmish internal void is a good thing.

I need to get a proper measurement on it but i think it is around 350-400mm and it has got bricks on the rear. 

 

Warm batten was my preferred method for quite a while but then i started to look at how the house is setup now which is gypliner 20mm off the wall with 15mm plasterboard over it. 

 

If i go warm batten i am changing the setup completely where as building a new stud 20-30mm off the wall and then putting in more insulation followed by double plasterboard is similar to what i have now only more robust. 

 

I am not an expert and your post i have read through there seems to be some highly knowledgeable people who will know far more than I, Your problem sounds a little more complex so may require an even more measured approach. Do you have some pictures of the building and the walls with the problems also?