Knauf Thermoshell internal wall insulation system - Solid Wall

booooonzo · 18-02-2019 12:17am #1

been doing tons of research on insulation approaches for solid wall homes and it really seems to be an issue the building industry struggles with if EWI is not an option.

Anyway found this article on a system from knauf used by an architect in his own home trying to reach a high standard.

https://passivehouseplus.ie/magazine/upgrade/victorian-upgrade-hits-80-energy-saving

Bar a few other bits and pieces though I can't find much on it. bit worrying.

has anyone come across it before?

There also seems to be this system from knauf called TecTem

https://passivehouseplus.ie/magazine/upgrade/radical-retrofit-transforms-pennines-historic-barn

which is perlite i believe.

We hope to do a room by room approach of IWI of a solid wall home and realizing it is not the safest approach, we are trying to mitigate the risk as much as possible.

Calahonda52 · 18-02-2019 12:44pm

What exactly is the solid wall built from?
Does it have a dpc?
Is it skimmed with gypsum?
What is the floor?
Does it have a dpc?
Are you considering MHVR?
Have you looked here: https://www.ecologicalbuildingsystems.com/Ireland
look at the stuff that gets glued onto the wall.

booooonzo · 18-02-2019 4:59pm

Calahonda52 wrote: »

What exactly is the solid wall built from?
Does it have a dpc?
Is it skimmed with gypsum?
What is the floor?
Does it have a dpc?
Are you considering MHVR?
Have you looked here: https://www.ecologicalbuildingsystems.com/Ireland
look at the stuff that gets glued onto the wall.

Hey,

Wall build up from outside in is

Render (cement but there is no damp or wet on any wall so far) [LIST=2]300mm deep walls of Brick and rubble
[/LIST]
[LIST=3]
lime plastered internal
[/LIST]
[LIST=4]
in some rooms there is dry lining with a stud frame 50mm of the wall with 100mm rockwool friction fitted and gypsum plasterboard over this.
I've knocked through in places and there is no damp at all.
[/LIST]

The floors vary from original suspended pine floor to poured, uninstalled (I'm guessing) concrete, prob with a dpm

Considering MHVR yes but have not done research in to how air tight the house needs to be for it to be effective yet.. but I see it's benefits alright.

Have looked on ecologicalbuildingsystems alright, which one are you referring to specifically? I have a good bit of wall to do and obviously budget will come in to it.

in regards to the walls having a DPC, i have no idea yet. possibly a slate one but ill need to verify

cheers

Muahahaha · 18-02-2019 6:22pm

Can't answer your question OP but am in the same boat. Have had a three quotes so far for IWI but it was hard to have much confidence in two of them, especially when one of them made a claim that internally insulating could save me up to 75% on my heating bills :rolleyes: The other one I asked about how they were going to deal with cold bridging and their answer wasn't great, I wanted to hear that they would be using airtight tapes and membranes at the junctions but this seemed beyond their station.

Then a week later I was getting a quote for new windows from a major company and I asked him about internal insulation companies and without prompting he told me to avoid the one company of the three that I thought was decent. To put the cherry on top this company are NSAI certified so you really wouldn't know what to believe at this stage. The company he did recommend look decent but they tell me all their resources are taken up at the moment doing SEAI work for county councils.

I get the impression that internal insulation can work well but that there are also a lot of cowboys out there who are more than capable of messing it up. Its hard to find decent independent feedback on the various companies and systems.

At this stage I'm thinking of asking around to see would an energy consultant spec the job, oversee it and sign it off as done to a good standard. Its a fair spend so important to get it right.

sydthebeat · 18-02-2019 6:50pm

Muahahaha wrote: »

The other one I asked about how they were going to deal with cold bridging and their answer wasn't great, I wanted to hear that they would be using airtight tapes and membranes at the junctions but this seemed beyond their station.

that wouldn't deal with any thermal bridge

Muahahaha · 18-02-2019 7:03pm

What would syd? How should internal insulation be specced to get the junctions with window reveals and floors as airtight as possible?

Calahonda52 · 18-02-2019 7:32pm

Muahahaha wrote: »

What would syd? How should internal insulation be specced to get the junctions with window reveals and floors as airtight as possible?

insulation and air tightness are two different things.
To deal with air tightness you need an air tightness layer
insulation then is fixed to minimise thermal/cold bridges.

OP: the lime finish on inside is great
look at GUTEX Thermoform

https://www.ecologicalbuildingsystems.com/Ireland/Products/Gutex/Wall

you need to think about a services cavity as well on the room side of the wall insulation

sydthebeat · 19-02-2019 11:08am

Muahahaha wrote: »

What would syd? How should internal insulation be specced to get the junctions with window reveals and floors as airtight as possible?

air tightness isnt the answer to cold bridges.

cold bridges are gaps in the insulation envelope where construction compromises a continuous layer.

so with internal insulation, every junction between an interior wall and external wall is a cold bridge... the junction between the floor and external wall is a large perimeter cold bridge, the junction between any intermediate floor and the external is a large perimeter cold bridge.

the truth be told, there are no ways to properly counter theses without a major deep retrofit renovation .... and thats why internal insulation is a cheaper, less effective solution than EWI.

booooonzo · 19-02-2019 12:35pm

Calahonda52 wrote: »

insulation and air tightness are two different things.
To deal with air tightness you need an air tightness layer
insulation then is fixed to minimise thermal/cold bridges.

OP: the lime finish on inside is great
look at GUTEX Thermoform

https://www.ecologicalbuildingsystems.com/Ireland/Products/Gutex/Wall

you need to think about a services cavity as well on the room side of the wall insulation

Cheers, Spoke with them and got some great advice and insights.
Pricing is high enough alright but want to do it right.
I'll prob try and visit their show room to get a look at the finished product.

Interestingly he mentioned a recent test of 2 rooms.
one with 100mm gutex and poor or no detailing around window revals
the other room only required 20mm with detailing around windows and that to match the 100mm performance.

Also he reckons something like 100mm can be excessive for a room and 60mm is a better balance. All depends on various other factors of course.

Good to know also that I just need to source a good local plasterer who is open to the idea of learning a few new details.

I may be wrong but I assume this will not qualify for the SEAI IWI grant due to not meeting target u-value?

booooonzo · 19-02-2019 2:57pm

Actually just reading through their blog and there is some excellent information there for anyone interested

https://www.ecologicalbuildingsystems.com/Ireland/Blog/

Muahahaha · 19-02-2019 5:03pm

sydthebeat wrote: »

air tightness isnt the answer to cold bridges.

cold bridges are gaps in the insulation envelope where construction compromises a continuous layer.

so with internal insulation, every junction between an interior wall and external wall is a cold bridge... the junction between the floor and external wall is a large perimeter cold bridge, the junction between any intermediate floor and the external is a large perimeter cold bridge.

the truth be told, there are no ways to properly counter theses without a major deep retrofit renovation .... and thats why internal insulation is a cheaper, less effective solution than EWI.

Thanks for the info syd. Can I ask what is best practice in IWI when it comes to linking the insulation boards to window reveals and floor junctions where cold bridges happen, what products/techniques should be used? I've heard of people just using expanding foam which sounds about as useful as a chocolate teapot.

booooonzo wrote: »

Good to know also that I just need to source a good local plasterer who is open to the idea of learning a few new details.

I may be wrong but I assume this will not qualify for the SEAI IWI grant due to not meeting target u-value?

AFAIK to get the grant your contractor has to be registered with the SEAI. I'd guess once they do then they are under guidelines to achieve a specific U value and their work may be subject to auditing. Also to get the grant you have to do the entire house. It is not clear if you have to do it all in one go but if you are intending to do it room by room as per your OP then make sure to clarify if this will exclude you from the terms of the grant.

Calahonda52 · 19-02-2019 6:27pm

Window reveals are not the same as a floor or internal wall Junction.

For the window head and reveals, you wrap the insulation around up to the window frame, with the thickness being limited by the window frame.

For interior walls, what is suggested is you come back in a meter and then taper it down to nothing: there are custom made products for that, you would need Amex:D
Floor junctions, impossible unless you do a complete gut job, aka Deep Retro

https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

might help

Muahahaha · 19-02-2019 7:49pm

Calahonda52 wrote: »

Floor junctions, impossible unless you do a complete gut job, aka Deep Retro

Thanks for the link calahonda, some good reading there for sure.

Just on floor junctions- if you were replacing the floor at the same time as dry lining then presumably that is a good opportunity to address cold bridges between the floor and wall? And what kind of technique/product would you recommend for this?

Knauf Thermoshell internal wall insulation system - Solid Wall

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