Is this board installed properly?

John Kelly of

Hi guys I am having attic converted. They put insulating board between rafters and covered that in a membrane, next battons will go on.
I peeled back some of the membrane this morning to look at the board and there are a lot of holes and gaps between the boards all over the ceiling and walls.
Builder says this is ok as the membrane will stop the draughts.
Surely this isn't right and it should be air tight where the boards meet the wood and each other?
Expert opinion would be appreciated thanks.

DOCARCH

Sloppy...that's what I would say. Insulation is only as good as it's weakest link. The gaps will leak heat. Insulation should be fitted tight together and tight to timbers.

fred funk }{

That's shockingly bad. It's lazy and they're fobbing you off. It's a tough job to do it right, especially on an attic conversion but that's no excuse. The heat will just leak through those holes.

Any gaps (normally small) should be filled with caulk and all joints covered with foil tape.

Calahonda52

As above
Rubbish job, period.

whats the roof felt behind?
Is it breathable?
Whats the membrane, looks like intello?

If u tape all the joints with Alu foil and maybe fill the gaps with foam before hand, then the insulation is impermeable because of the all foil so what purpose does the expensive membrane serve?

Have a read of this
https://www.nsai.ie/S-R-54-2014-Code-of-Practice.aspx

DOCARCH

Calahonda52 wrote: »

If u tape all the joints with Alu foil and maybe fill the gaps with foam before hand, then the insulation is impermeable because of the all foil so what purpose does the expensive membrane serve?

Indeed. Membrane does not serve much purpose with rigid/foil insulation.

Bullocks

That's fairly rough . I'd get him to take off any membrane and spray foam them joints and replace any insulation that has a gap bigger than 20mm

John Kelly of

thought so thanks for that info guys

bertie 56

Hard to do worse than this... :mad:

Your builder should have use flexible insulation, between timber.
Rigid insulation is only good in places that don't move, under slabs, for example.
In places where there is timber, the best is to use flexible slabs, as Rockwool / Hemp / sheepwool, etc...
I don't know the full specs of your roof, but cellulose might have been even better for covering all the gaps.

Good luck for doing something proper with what you have.

Calahonda52

John Kelly of wrote: »

thought so thanks for that info guys

Can you tell us what the membrane is please?

John Kelly of

Hi Calahonda52 its called Intello
tile roof then felt then those xtratherm boards between rafters which I have now sealed up all those cracks and joins as best as practicable after using 6 or 7 tins expandable foam and some wooly insulation. Next he put the membrane but he is now taking that down and instead we are putting up another layer of 40mm insulating board crossways on the rafters.
Then the membrane will go back up an below that, then battens and below that plasterboard.
The cavity between the battens will have the wiring for downlights.
I reckon it will be pretty snug now with the extra layer of 40mm board as well.

Calahonda52

I presume pro-clima intello plus.
OK, you are where you are but using one of the most expensive, if not the most expensive membrane in such a construction is quite frankly a waste of money because the ALU foil on the insulation board makes the roof structure impermeable.
If the tile felt is the black tile felt then more impermeability.

The job will be snug etc etc but I just don't see why you should be paying top dollar for a material which will not function as its "paid for" to do

From here
http://www.ecologicalbuildingsystems.com/Ireland/Products/Product-Detail/pro-clima-Intello-Plus

Provides optimum protection for all thermal insulation systems in roofs, walls and floors.
Offers high diffusion tightness in winter and maximum diffusion openness in summer.
In winter, its high diffusion resistance provides ideal protection for the building's structure against condensation.
In summer, its low diffusion resistance facilitates rapid drying.
It is translucent, easy to install, fully recyclable.
It offers the ideal solution to structures that are difficult to protect against condensation e.g. flat roofs, flexible metal sheeting, etc.
Intello Plus provides lasting protection against mould growth, thereby protecting the health of the occupants and ensuring structural durability.
Meets with the durability requirements of EN 13984.
Has a very high nail tear resistance due to reinforcing layer.

John Kelly of

Well the architect who did the plans had that in them anyway. How much does it cost per m2?
There are tiny holes all over it now from where they pulled it down where it was stapled so would that reduce its effectiveness when it goes back up?
Also for downlights they have holes in the insulation with small upsidedown flowerpots above where they will be located to give them air. Just thinking with led downlights is there any need for this seeing as they don't give off much heat at all?

Calahonda52

Okay, did the architect spec the Alu foil as well or did the builder change it, happens quite often.

Holes can be covered with the proper airtightness tapes, not gaffer or duct or gorilla

Post a pic of the downlighter, is the hole all the way back to the tile felt?

Re price/roll call Athboy on Monday and ask them, My rate is a special one as I do a lot with them.

Metric Tensor

The "back" of the LED unit gets quite warm when running. You'd be surprised.

Bullocks

John Kelly of wrote: »

Well the architect who did the plans had that in them anyway. How much does it cost per m2?
There are tiny holes all over it now from where they pulled it down where it was stapled so would that reduce its effectiveness when it goes back up?
Also for downlights they have holes in the insulation with small upsidedown flowerpots above where they will be located to give them air. Just thinking with led downlights is there any need for this seeing as they don't give off much heat at all?

There should be no holes so make sure to patch them up with tape , any recessed lights I've seen lately are boxed in ply giving enough room for the light fixture and sealed with tape ,membrane and the wire hole plugged with gum .
I hate to see builders getting away with half arsed measures in air tightness . You can be sure if it was there own house there would be attention to detail shown in case they might get a draft on their necks down from a light. !

antiskeptic

Would nobody be worried about having a builder capable of such crap work on site at all? Where is the botch work going to stop?

Bullocks

antiskeptic wrote: »

Would nobody be worried about having a builder capable of such crap work on site at all? Where is the botch work going to stop?

I would , keeping the insulation snug and cut tightly is pretty simple . I would be watching him like a hawk from here on in .
Now in saying that maybe everything else will be well done and the insulation might have been done by a labourer that was less than careful and the builder will put it right

antiskeptic

Bullocks wrote: »

.. the insulation might have been done by a labourer that was less than careful and the builder will put it right

To quote the OP

"Builder says this (that is: tombstone sized gaps in insulation) is ok as the membrane will stop the draughts"

I dumped a dodgy builder off site once - he was a few weeks into a house refurb project of mine .. and a couple of tradesmen thereafter on account of shoddy work. Painful and troublesome. But the alternative leaves me shuddering.

rampantbunny

Bullocks wrote: »

I would , keeping the insulation snug and cut tightly is pretty simple . I would be watching him like a hawk from here on in .
Now in saying that maybe everything else will be well done and the insulation might have been done by a labourer that was less than careful and the builder will put it right

To be fair Bullocks, if you have to watch someone like a hawk to get the job done right then it's just not worth it. If his laborers did it then the builder was/is ultimately responsible.
Putting it right only if he is caught out...and invariably putting things right is still no substitute for it being done right in the first place.

Bullocks

rampantbunny wrote: »

To be fair Bullocks, if you have to watch someone like a hawk to get the job done right then it's just not worth it. If his laborers did it then the builder was/is ultimately responsible.
Putting it right only if he is caught out...and invariably putting things right is still no substitute for it being done right in the first place.

No it's not worth having to watch someone like a hawk , but I'm hardly going to suggest not to bother watching the builder now .
At this stage that type of work can be redone every bit aswell as it should have been the first time .

rampantbunny

Bullocks wrote: »

No it's not worth having to watch someone like a hawk , but I'm hardly going to suggest not to bother watching the builder now .

No one is suggesting OP shouldn't watch the builder but unless he/she is there every minute watching all jobs at same time then this is not practical.

Bullocks wrote: »

At this stage that type of work can be redone every bit aswell as it should have been the first time

Only because OP found issue in time. Unfortunately, won't always be so 'lucky'. But maybe builder will learn a lesson and recognize the OP checks everything..I wouldn't be counting on it myself though.