Demands of engineer for final cert for last drawdown. Please advise

Hi just a few questions.
We've just gotten a list of jobs to be completed before the engineer will sign off on the property to release our last drawdown and I'm a bit shocked at what has come up. We have renovated a 3 bed bungalow which was built in the 70's. We basically gutted the house and built on an entension.
Problem 1. He wants us to put 300 mm of fibreglass into all attic space. We have already put 6inches of spray foam insulation on the underside of the roof. The company who did this said we don't need fibreglass to fullfill regulations.
Problem 2. He wants us to put vents in all the rooms. We have vents in the extension where there is a gas hob. The house is heated exclusively by geothermal heating and am I right therefore in thinking that carbon monoxide is not a consideration for us? Why therefore do we have to fit vents in the old part of the house? Is this a big job?
I have emailed him about all this but I am awaiting a reply

Have you discussed these points, particularly the vents, with whoever designed the house for you?

Well the engineer is also the architect so he designed the extension. The existing part of the house where he wants us to retrofit vents was built in 1972. The extension has vents already.

Does the insulation used have IAB certification? The company should be able to supply evidence to satisfy the engineer if the product used is up to standards. Saying it's OK isn't good enough.

The vents are required to meet building regulations. Unless you have mechanical ventilation, you need vents in all rooms. It's not a big job to put these in now, but should have been planned for during construction.

I'd be concerned about the detail specification of this work. Is he qualified in both fields? Did he detail the insulation and ventilation on the plans given to the builder?

I've moved this to 'Sites, planning, self-builds and extensions' where you'll get a better response.
Leo

celine26 said:

The existing part of the house where he wants us to retrofit vents was built in 1972. The extension has vents already.

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Is this the first time he has mentioned the vents in the existing house? Was it covered on his previous advice or drawings, or scope of works?

In general, building regs apply to the changed part of a property only, unless there is something specific in the regs about vents.

Leo said:

Does the insulation used have IAB certification? The company should be able to supply evidence to satisfy the engineer if the product used is up to standards. Saying it's OK isn't good enough.

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Yes if the insulation was installed by a seperate company, then that company should provide written documentation saying that the attic roof space conforms with Part L, stating the achieved U-value of the spray foam. However insulation to a dwelling falls into the expertise of an architect, hence why I have attached this document for your information.

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,19069,en.pdf

Leo said:

The vents are required to meet building regulations. Unless you have mechanical ventilation, you need vents in all rooms. It's not a big job to put these in now, but should have been planned for during construction.

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Yes and No. You will require vents to all rooms except where there is a permanent opening between two rooms. As it is not my expertise, as I am an Engineer only, I would suggest you have a look over the attached building regulations document.

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1647,en.pdf

Leo said:

I'd be concerned about the detail specification of this work. Is he qualified in both fields? Did he detail the insulation and ventilation on the plans given to the builder?

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I likewise would be very concerned that your Engineer is also acting as your Architect. Is he qualified to address your two issues as above, as they both fall in the category of the Architect's expertise?

+1 what others have posted and I'll add the following.

An engineer is competent in his own field, which is usually that of structural, civil, mechanical or electrical design.
Engineers are not trained to specify domestic extensions never mind period refurbishments, as there are a whole slew of issues where different forms of construction are used.

The difference between architects and engineers may soon become apparent to the OP if problems of interstitial condensation, water penetration and cold bridging rear their heads.
The lack of an architect on a job like this may have already caused problems in the old part of the building, which sounds like its been sealed up structurally, when really it needs to breath.

Such work is not an easy to carry out and my preferred method of addressing it is to allow the two different technologies to co-exist via a link, and not try to force square pegs into round holes.

ONQ

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All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.