External insulation and ventilation upgrades

Stealthirl · 20-11-2022 12:32AM #1

I had a company out to quote for EWI and wanted to ask here for any recommendations or questions to ask them before i sign the contract.

Currently, on my list is tapping the windows, refitting my car charger and fascia and soffit replacement. Is it worth asking for single room heat recovery units instead of background vent?

The house was built in 89/90 and has a C3 rating. Since that BER we have changed windows and doors, insulated the attic and internally insulated 2 rooms with 100mm (where this quote has to be be pumped) we haven’t done anything internally on the 3rd room yet as it is mostly window(converted garage)

I've included some of the quote below

MicktheMan · 20-11-2022 02:04AM

For starters...

Will the insulation go up past the soffit to meet the attic insulation and down to the footings (i.e. below ground level)? If not, why not?

Stealthirl · 22-11-2022 06:23PM

I don't think any of the retrofit companies go below ground level, least none iv seen getting done, they do plinth level. I would persume it would go all the way up to meet the attic insulation but will ask for clarification on that, Thanks

TimHorton · 22-11-2022 08:52PM

https://www.boards.ie/discussion/comment/119907869#Comment_119907869

https://passivehouseplus.ie/magazine/upgrade/cork-bungalow-upgrade-phased-over-12-years This is MicktheMans House , He always mentions going 600mm below internal finished floor - I am not in the building trade but have seen lots of external wall insulation jobs being done and not seen a single one going below ground level.

Even the QS from Room to Improve seems not to require going below ground level ! https://www.youtube.com/watch?v=aptnRet7l-E

MicktheMan · 22-11-2022 10:38PM

https://www.boards.ie/discussion/comment/119907869#Comment_119907869

Presume nothing and clarify everything ... in writing.

You are correct, the vast majority of ewi works you see being done do not :-

go below ground level
go up past the soffit
bring the windows out flush with the old external wall plane

Just because the ewi contractor wants to do the work as cheaply and quickly as possible doesn't mean that this is best practice especially when it comes to creating thermal bridging and the corresponding risk of damp & mould internally.

Also, I've visited quite a few externally insulated houses where the occupants were less than impressed with the result because no attention was initially paid to the heat being lost through air leakage rather than insulation.

TimHorton · 23-11-2022 07:56AM

https://www.boards.ie/discussion/comment/119909060#Comment_119909060

Mick are there any enforceable regs/standards relating to EWI ? - "Best Practice" is nonsense, No contractor will take on a job for the regular joesoap if it were to be done to your requirements (Would be too expensive) Contractor will quote for EWI and you will get their version of EWI as there are no standards to follow , That's why customer awareness is so important,

Lumen · 23-11-2022 12:18PM

https://www.boards.ie/discussion/comment/119909816#Comment_119909816

The NSAI certs contain details.

e.g. from a couple of common systems

Baumit 60 External Insulation Systems

Plinth and perimeter boards are then fixed to the wall below the base profile to provide the necessary resistance to impact and capillary action. To minimise the effects of cold bridging, the plinth board should extend below ground level where possible. Where this is not possible the first run of plinth boards is positioned at ground level.

Soltherm External Thermal Insulation Composite Systems

At plinth level, XPS boards are then fixed to the wall below the starter track to provide the necessary resistance to impact and capillary action. To minimise the effects of cold bridging, the XPS boards should extend below ground level where possible. Where this is not possible, the first run of XPS boards should be positioned at ground level as detailed in Figure 1.

Source: https://www.nsai.ie/certification/agrement-certification/search-agrements-certificates/

then search by Product Area = External Insulation

FWIW I have a spreadsheet of all the external insulation systems, their certs, and their registered installers which I could dump here if anyone is interested.

Lumen · 23-11-2022 12:21PM

Relatedly, I've probably posted this before but it's quite interesting from a detailing perspective.

Post_Installation_Performance_of_Cavity_Wall__External_Wall_Insulation.pdf

Lumen · 23-11-2022 12:23PM

...and whilst I'm dumping docs...

Deep-Retrofit-Quality-Assurance-Document.pdf

Scoopsire · 25-11-2022 10:52PM

https://www.boards.ie/discussion/comment/119910523#Comment_119910523

It would be great if you could share the spreadsheet.....def corners being cut, saw it in my estate....no attention to detail cold bridges everywhere

Lumen · 26-11-2022 10:17AM

https://www.boards.ie/discussion/comment/119922183#Comment_119922183

Sorry it's a bit rough, but someone might find it useful, one of my Saturday morning projects!

https://docs.google.com/spreadsheets/d/e/2PACX-1vQp-90ul0T91ZAddfPEBDmEfw_YzidYcCEN3-VXlm_vkPd7R6sjCXfmGdwJLziqUhp4gvDGU0M-xGI3/pubhtml#

The Pilot Project referred to within is this:

External-Wall-Insulation-Project.pdf

And here's another doc that might be useful.

Acceptable Construction Details TGD PartL Building Regulations 2021- External Wall Insulation.pdf

TimHorton · 26-11-2022 10:36AM

https://www.boards.ie/discussion/comment/119910547#Comment_119910547

So no actual enforceable regs just SEAI Grant stuff that currently nobody uses for deep retrofits.

TimHorton · 26-11-2022 10:39AM

https://www.boards.ie/discussion/comment/119922183#Comment_119922183

So a punter spends 80k on a deep retrofit and a follow up survey shows is it was botch job - What are his options ?

Lumen · 26-11-2022 10:43AM

https://www.boards.ie/discussion/comment/119923880#Comment_119923880

I'm not really sure what you mean by "legally enforceable" in the context of Irish construction. By whom, and against whom?

TimHorton · 26-11-2022 10:49AM

https://www.boards.ie/discussion/comment/119923897#Comment_119923897

So a punter spends 80k on a deep retrofit and a follow up survey shows is it was botch job - What are his options ?

Lumen · 26-11-2022 11:13AM

https://www.boards.ie/discussion/comment/119923911#Comment_119923911

Take legal action against the installer, obviously, but that sort of approach (pay someone and sue them if they **** it up) is never sensible in any walk of life.

The better question is: how do you make sure it's done right in the first place?

Long-list a few installers, RTFM on the systems (NSAI certs and installation details from system mfrs), highlight all the critical details, get them round to do a quote, ask them specifically about the critical details, and if you're happy with the responses, make sure they're all recorded on the quote, and then closely supervise the works as they're going on to make sure nothing is missed. Possibly pay a professional (arch tech?) to do some of all of this for you, but that's going to add a bunch of costs. If anyone has a better idea I'd like to hear it.

I'm in this process right now, and it's even harder as I have to co-ordinate a bunch of related construction works to tie in with the external insulation.

At least with something like air tightness (in a new build) the performance is testable during construction, so you can put a specific target in the docs and then blower-door test and fix until it's met. How are you supposed to test external insulation performance?

TimHorton · 26-11-2022 11:19AM

https://www.boards.ie/discussion/comment/119923973#Comment_119923973

So its up to the customer to make sure the job is done correctly , I follow a couple of Construction Youtubers in New Zealand and the USA , At every stage of even a small renovation they are inspected by building control to ensure the job is done correctly

Lumen · 26-11-2022 01:15PM

https://www.boards.ie/discussion/comment/119923989#Comment_119923989

I agree that the State's abrogation of any direct responsibilty for enforcing building standards is pathetic, but what practical use is that? Do you have a petition I can sign? 😀

External insulation and ventilation upgrades

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