what roof insulation can you recommend

1noelsattic

looking at several different thing son web about roof insulation as we are converting out attic. Has anyone some suggestions on what is best suited. The depth of the rafter is 100 mm so ideally looking for insulation with a depth of around 80mm. Have already checked B & Q and most of the other builder merchant stores are closed, B & Q dont have much when it comes to roof insulation

RKQ

There are lots of threads on insulating your attic.
I'd suggest 100mm fibre glass quilt between your joists and 200mm fibre glass perpendicular to the joists, giving a total thickness of 300mm. Maintain adequate cross-ventilation of attic ie ensure a minimum gap of 50mm between underside of roof felt and top of insulation at eaves.

Insulate all exposed pipework with armaflex insulation. Insulate sides and lid of water storage tank - but do not insulate underneath the tank. Insulate the attic access hatch door & install a rubber draught excluder around its perimeter.

1noelsattic

HI RKQ

Thanks for the sound advise on the roof insulation. I think most of the building merchants are closed until this monday so i shall start making calls then to get prices etc. There is alot more to this that meets the eye but again thanks for the advise. Is there any particular brand or particular merchant store that you would suggest for the above materials

Thanks Noel

RKQ

Hi 1noelsattic,
You are very welcome. I'm glad to help if I can. I don't particularly have a recommended brand, merchant or store - check them all out.

Fibre glass is fibre glass and all the big DIY stores are open this weekend - they all tend to have special offers on insulation, at this time of year. I bought a lot last year in a "Buy one get one free" offer.

Rockwool would be more expensive but its easier to lay as the fibres don't irritate skin and eyes as much as fibre glass can. Compare the u-value of "recycled plastic" insulation with fibre glass to check it insulates as effectively. Good luck.

eoghan.geraghty

Noel if you have 100mm rafters on your roof you would be better with 50mm extruded polystyrene,either kingspan or xtratherm, leaving a breathable area of 50mm.
IIRC any attics i wired for people had 150mm rafters so they were able to use 100mm polystyrene.
If you can only use the 50mm then I would advise you slabbing the new ceiling with 38mm thermal board.

ab20

The industry regulation is for 100mm Kingspan insulation board. This is equivalent to about 400mm of fibre glass or rockwool insulation. It used to be about €60 a sheet. Expensive but when it comes to getting a BER Cert if you have to sell your house. Go to any of the Big DIY shops and they should have some there to show you. You could always ring Kingspan and ask then what the general retail price is for it. It should be cheaper now.

1noelsattic

Hi Ab20

thanks for the reply. I see you mentioned 100mm of kingspan for roof insulation. My problem is that the depth of the rafter is 100mm and i gather that one is to leave a breathing space between the insulation and the felt, so using the 100mm kingspan will leave me with no breathing space unfortunately

Delta Kilo

Just to note that there are grants available to carry out insulation work on your home so you should look into this.

EDIT:Therefore you should look into getting a professional firm into doing it for you. They would probably use the stuff that they spray out of a gun. They will be able to tell you all about the grants and BER certification too.

No harm in getting a quote anyway.

1noelsattic

Hi Delta Kilo

Thanks for the above. I am aware of the SEI grants as we used one ourselves to install a new boiler. My only problem with the SEI grants is that you have to use one of their nominated guys to do the work and the labour charge is huge considering I can do it myself with my father slowly and get it done right. Thanks for the suggestion anyway

Noel