Plasterboard in the loft

[con1_uk]

STILL underway with the old loft conversion its coming along slowly.

I had the roof sprayed with foam, this maintains the U Value required and its thickness is the same as the rafters so I can maintain a good head height.

Im upto plaster boarding it all but im not sure if I should use foil backed boards or plain boards? Also which thickness should I go for?


Thanks in advance,

Con1_uk.

 

[markie]

Hi, con1_uk

Just out of intrest, when you said you had the roof sprayed with foam can you give abit more info.

The reason i ask is that you have to maintain a air gap if you are going to board over the rafters, 2" air flow if by the regs.

All you need is 3/8 plaster boards, and regarding foil backed boards it might be cheaper to buy a roll of thin clear plastic ( T.P.S ) and nail it to the rafters before you nail/screw the boards on.

 

[jbonding]

STILL underway with the old loft conversion its coming along slowly.

I had the roof sprayed with foam, this maintains the U Value required and its thickness is the same as the rafters so I can maintain a good head height.

Im upto plaster boarding it all but im not sure if I should use foil backed boards or plain boards? Also which thickness should I go for?


Thanks in advance,

Con1_uk.

Is the building inspector involved?

 

[con1_uk]

Yes. Plans passed work commenced.

 

[con1_uk]

Sorry missed the 1st reply.

Its a foam that is sprayed to the underside of the slates and holds them on to the roof. It was done by a company called Sprayseal. It is a breathable foam and requires no air gap both the Inspector and Sprayseal man say the boards can be fitted straight to the rafters.

Ta.

 

[legs-akimbo]

Oh dear, Those spray systems cause more problems than they solve, sorry to say this but you have gone down the wrong path here, but too late to turn about now so do use foil back for a degree of heat reflection that should have been implemented with the use of kingspan insulation (between rafter). I would counter batten the rafters to at least leave an inch gap between board and insulation if it is full fill between rafter. Do make sure you receive full guarantees from the company just in case.

 

[con1_uk]

Im quite happy with the Sprayseal job it sorts out the roof keeps the slates in place stops considerable noise pollution from outside (We live on a main road) and the house is much warmer now.


What problems has there been with this stuff?

Thanks,
Con1_uk.

 

[masona]

What problems has there been with this stuff?

Have a read here

 

[jbonding]

Yes. Plans passed work commenced.

dont the plans show which plasterboard to use?

 

[con1_uk]

Nope the plans don't state I was just looking for the best solution.



Thanks for the Sprayseal Info it did work out a lot cheaper to have the roof sprayed and garanteed than to have it stripped and re-slated I understand the risks and would probably do it different next time.
I did use the foam because I didnt lose any headroom.

I had 2 options

Option 1
Remove slates and re felt re fit slates
Buy Kingspan

Option 2
Spray the slates


Option 2 was much cheaper than option one and provided much better noise insulation. Building control was happy with the stuff and I spoke to them before and they inspected after.


So do I go for the foil backed or the normal stuff?

Thanks.

 

[legs-akimbo]

You have to a degree solved your insulation problem in so far as keeping the room warm, but in doing so you have created the problem of also keeping it cool in the summer. Consider the fact that slates can heat up to around 70 degrees under a blazing sun, this heat is then transfered inside your loft and it will be like an oven in there. Had you used double foil backed between rafter insulation the intense heat would have been reflected from both the outside and internally tooin winter. You have also in effect completely sealed the roof allowing for no through ventillation whatsoever which I am surprised has been allowed by B.C. as this flys in the face of all regs, using foil backed boards will give partial heat reflection.