Insulation for attic conversion (boards V spray foam)

fitzparker

We are currently getting attic converted and looking for opinion on Insulation.

Kingspan insulation boards come with the price, for €1000 more we have the option of spray foam.

it is a bit out of budget but if the difference in insulation huge it is something we would consider, my brother (in same estate) got boards in his conversion last year and he said its fine.

our attic will be about 20 foot x 13 foot

1. is there a major difference?
2. is the price justifiable for that size

Bazzzzzza

Hi - just wondering what you did in the end or whether you ever got advice on whether foam or plasterboard is best in terms of insulation? We’re in the middle of converting our attic and have the same question…

youcancallmeal

We're planning to get our attic converted in a few months and the crowd doing it recommended spray foam as our house is already an A3 BER. They reckoned if it isn't an already very well insulated house then just go with rigid foam(i.e. kingspan). I did hear from someone else though that their attic converter recommended not using spray foam at all as there is nowhere for moisture to escape resulting in rotting roof rafters over time. Hard to know if there is any truth to it or just a builder who doesn't want the hassle of having specialists in to do the spraying.

C. Eastwood

Do not use spray foam.

The Building Regulations (BR) 2019 require Ventilation of the roof void of a domestic dwelling. 

The minimum ventilation requirement are set out in Technical Guidance Document (TGD) ‘F’ Ventilation. - here is the Diagram 11- Ventilation of Roof Voids, from this document- which shows the minimum requirements

A90EBDE8-4498-4263-B9E1-ED34867B93AB.jpeg

If what you plan to do is not shown here, then do not construct it, as it will not be in Compliance with the Building Regulations. 

Fresh air is wonderful for building materials. Timber with a little extra moisture and lack of ventilation will enable Dry Rot to flourish.

The Building Regulations have 5 purposes, 3 of which are as follows:- Health, Welfare and Safety of persons.

Remember when you are dealing with human beings- and they say “that this is the best thing to do”.

they never finish the sentence which is as follows:- “ that is the best thing to do for us to take as much of your money as is possible, and do as little as possible”.

Deregos.

There's an old house near me being flipped for resale. They got some lads in to spray foam between the rafters directly onto the underside of the blue bangers cause there was no felt. Any of the loose-ish slates sort of rose up a bit & twisted from the foam expanding between the gaps leaving it all looking very bockety.

Just to top that off they sprayed the slates with what looked like black emulsion which started to flake off almost immediately, now the whole roof looks like shite.

Am i right to assume that when it comes to being sold on, none of the engineers doing a report for potential buyers of this house, are gonna wanna let there clients anywhere near it because of the way the roof was treated?

C. Eastwood

Deregos.

This goes to show that the Expert Foam Insulation Sprayers haven’t a clue.

Many people getting their homes insulated with these experts - with the new Home Insulation Grants Scheme will end up with terrible building problems and mental health issues

A Building Surveyor carrying out a Structural Home Buyers Survey on this house, would state that the entire roof must be replaced, and obtain an Estimate from a Building Contractor for same.

jack of all

I work for an engineer that does a lot of pre- purchase inspections/ structural surveys and he is very wary of spray foam in general. You don't know what is going on behind the foam or what is the condition of structural timbers covered up like this. At least with a conventional dormer with quilt or board insulation you have the option of investigating the build up, even if this means making some holes in a plasterboard lining for a boroscope. The situation outlined in the example above is vandalism as the slates will not be recoverable for reuse and any water ingress is trapped which will accelerate any existing deterioration.

C. Eastwood

Jack of all

Vandalism is a brilliant description of the foam in the Blue Bangor Roof.

The subsequent charging for the painting of the slates with black emulsion could be described as Theft.

Deregos.

https://www.boards.ie/discussion/comment/118801200#Comment_118801200

Part of the crime scene.

C. Eastwood

Deregos

Unbelievable.

They should be prosecuted for causing that terrible damage to someone’s home, and made return all the money.