External and Internal Insulation on same walls

jay0109

Hi

I've been googling this and searching here and cannot seem to find any real discussion on this.
Most, but not all, of the walls in my house that I bought a few years ago are internally insulated. I had an SEAI rep out recently and he's recommended getting the external walls all insulated (pumped on the front of the house only, wall panels on the rest) and he has set the wheels in motion on getting it done.

Will that cause issues in the house with both internal and external walls insulated i.e condensation in the wall between the 2 insulation types, or will adequate air vents solve that?

thanks

BryanF

SEAI rep? Do you mean a contractor?

What is the build up of each type of wall from inside to outside? Ie insulsted plasterboard, plaster, block, cavity? (Or cavity block?) block? Render. Etc

jay0109

Hi Bryan, I was hoping you'd respond!

We qualify for the SEAI Warmer Homes scheme and so their rep was out last week to see what work could be done under the scheme. Contractor will follow in a few weeks to go through the work outlined by the SEAI rep.

I have no real idea of the walls but as I understand it....there's a pebble dash render, single block (not the cavity type that can be pumped) and internal insulation boards.

Dudda

jay0109 wrote: »

Hi Bryan, I was hoping you'd respond!

We qualify for the SEAI Warmer Homes scheme and so their rep was out last week to see what work could be done under the scheme. Contractor will follow in a few weeks to go through the work outlined by the SEAI rep.

I have no real idea of the walls but as I understand it....there's a pebble dash render, single block (not the cavity type that can be pumped) and internal insulation boards.

Generally it's best to have all the insulation in one place but nothing wrong with it both inside and outside if it's done right. If you've an SEAI rep hopefully it will be done right.

With regard to the pebble dash I'd consider getting that plastered before any external insulation is added. You want the external insulation tight up against the external wall and that pebble dash is going to create a gap or tiny void for air and moisture. You could try hacking off the dash but you'd never get it smooth. The lazy contractor option will be to use some expanding foam between the insulation and the pebble dash. I'd avoid this as they'll do it in areas where it suits.

jay0109

Thanks Dudda, that makes sense and seems like very good advice. I'll raise that with the Contractor when he makes his site visit in the coming weeks.

BryanF

As above, contractor must foam/close gap on all 4 sides of insulation to wall and between insulation slabs. Quality control is the issue. Detailing around ground,windows, eaves, fownpipes, cables etc is also a challenge as the contractor will take any ambiguity available

jay0109

I just spoke to someone who has had similar work done and was told that the Contractor will apply EPS boards to the external wall at 16 points. The boards, as they are essentially like Styrofoam, will form around the pebble dash. And that method comes with the blessing of the SEAI.

Wartburg

jay0109 wrote: »

I just spoke to someone who has had similar work done and was told that the Contractor will apply EPS boards to the external wall at 16 points. The boards, as they are essentially like Styrofoam, will form around the pebble dash. And that method comes with the blessing of the SEAI.

Get the pebble dash straightened by taking protruding pieces off or adding plaster. Conventional ETICS require a smooth service and should be placed as close as possible to the wall, to prevent thermal looping. Also, every board has to be bonded to the wall by being separately sealed all around. Dabbing will create thermal looping again. A quick demo from STO can be found on the internet. https://youtu.be/xED_L8oQ0OA It is in German but more or less self-explaining.

There is a self-levelling external wall insulation system available, which is made of wood fibre. These boards have a soft insulation at the back of each panel, which allows a levelling of uneven surface up to approx. 20mm. But as always - serious problem solver are available for an additional charge.

jay0109

Wartburg wrote: »

Get the pebble dash straightened by taking protruding pieces off or adding plaster. Conventional ETICS require a smooth service and should be placed as close as possible to the wall, to prevent thermal looping. Also, every board has to be bonded to the wall by being separately sealed all around. Dabbing will create thermal looping again. A quick demo from STO can be found on the internet. https://youtu.be/xED_L8oQ0OA It is in German but more or less self-explaining.

There is a self-levelling external wall insulation system available, which is made of wood fibre. These boards have a soft insulation at the back of each panel, which allows a levelling of uneven surface up to approx. 20mm. But as always - serious problem solver are available for an additional charge.

That bit in bold- the SEAI seem to be saying the EPS boards will do that. The softness of them on 1 side means they will go ssnug up against an uneven service.
Will follow it up

BryanF

Have a read of the systems certification & installation manual. The SEAI are not offering you a product guarantee.

Bullocks

jay0109 wrote: »

That bit in bold- the SEAI seem to be saying the EPS boards will do that. The softness of them on 1 side means they will go ssnug up against an uneven service.
Will follow it up

I've never seen boards that are soft on one side that would envelope the stones from pebble dash .
The mineral wool would be soft alright .

Wartburg

Bullocks wrote: »

I've never seen boards that are soft on one side that would envelope the stones from pebble dash .
The mineral wool would be soft alright .

There´s always something new, that hasn´t found its way to Hibernia so far.
https://udidaemmsysteme.com/en/udisystems/for-the-facade/facade-detail/artikel/udirecor-sy.html

booooonzo

Just an FYI

I got a quote for the UdiIN RECO system with soft backing for internal wall insulation vs Gutex which is solid

approx €100 m2 vs 65 m2 including all plasters etc..

So the soft backing adds on a good bit. Might be cheaper to hack off/smooth off the wall

Wartburg

booooonzo wrote: »

Just an FYI

I got a quote for the UdiIN RECO system with soft backing for internal wall insulation vs Gutex which is solid

approx €100 m2 vs 65 m2 including all plasters etc..

So the soft backing adds on a good bit. Might be cheaper to hack off/smooth off the wall

I´d be interested which company worked out the quote for the UdiIn RECO.

booooonzo

Wartburg wrote: »

I´d be interested which company worked out the quote for the UdiIn RECO.

It was an english company in devon, Ill pm you the name.
in fairness it was the delivery that killed it. £500 for the pallett

Wartburg

booooonzo wrote: »

It was an english company in devon, Ill pm you the name.
in fairness it was the delivery that killed it. £500 for the pallett

Thanks for the info. The company in Devon is a decent one, even by never been in contact with him personally. There should be an option to optimise the delivery costs. I heard pretty often that British suppliers do charge an arm and a leg for shipping to Ireland, whilst you get goods from Central Europe shipped for half the amount.

BryanF

Comments or recommendations on specific companies by PM thanks

jay0109

I was walking by a pebble dashed LA house last week which was getting an external insulation job done by 1 of the main SEAI approved companies in Dublin. I stopped to ask the lads on site how they were dealing with the pebble dash issue and though they didn't have great English, they were able to show me what they were doing.
Basically, the apply foam/filler around the inside edge of the insulation board on those boards only that end in 'open air' i.e. the boards at door ways, windows, the last in the line of the boards at the top/bottom/side of the house.

Thoughts?

BryanF

Should 4 sided seal to wall on all boards imo

metricspaces

booooonzo wrote: »

It was an english company in devon, Ill pm you the name.
in fairness it was the delivery that killed it. £500 for the pallett

Did you try getting your own price for a pallet collection from UK and delivery to Ireland? I've used these before http://tpn.ie/

Some companies in UK will deliver to a UK port cheaply and then you just pay for your courier to pick up from the port. Or it may just work out cheaper for your courier to pick up from Devon.