Insulation Query

pologirl

Hi There,
I have recently built a dormer house, and i have some insulation questions/concerns which i hope you kind people here can help me with.

1. Downstairs between the cavity i put in a grey foam type insulation that fits into each other.(sorry not that technical!) if this is not sufficient can i get the pumped in stuff later? i put 60mm cosy board on all external walls i got a young guy to do my insualtion (big misake he did not do a great job) anyway the house is now all skimmed inside,
2. behind the sloping roof i have Quinn therm between the joists, and then ordinary slabs over it, (should i have installed cosyboard insulated plasterbaord instead? )
3. on the walls upstairs i also have quinntherm between the joists and it was suggested to me that i removed the quinntherm and place a sheet of fibreglass done along inbetween the joists and then cover this over again with my quinntherm, would this be advisable and would it be benefical? (i have openings left so its possible to get at these areas) thankfully!
4. The attic at the moment has 100mm of fibre glass i intend up upgrade this but am unsure what to put into it would quinntherm be better than fibreglass here?
5. Sound insulation - betwen the floors i put fibreglass and some rockwool. i have been advised to put down either blue acustic slabs or a black rubbery type romaterial that comes in roles to help with sound, do you think this would be usefull?
6. One final question how are you supposted to insualate around dormer windows? most of mine are in bathrooms and since i will be tiling over these i was thinking of adding a 60mm think cosy board sheet over my skimming, then tile away, would this be worthwhile?

thanks very much
all help appreciate, im a woman building alone so dont want to be talked into anything anymore!

thanks again
pologirl.

AckwelFoley

Downstairs between the cavity i put in a grey foam type insulation that fits into each other.(sorry not that technical!) if this is not sufficient can i get the pumped in stuff later?

Its not sufficent to comply with todays regs unless you are sticking an insulated slab to the walls inside, which i see you have, im not an expert in u values, but i think its tight.. but yes you can get it pumped with insulation beads at a later date. Make sure its an adhesive bead or else its worthless as the other beads sagg in time leaving the top near your ceilling uninsulated which is where the best insulation needs to be!


behind the sloping roof i have Quinn therm between the joists, and then ordinary slabs over it, (should i have installed cosyboard insulated plasterbaord instead? )

Its best you do both, cosyboard is not sufficent on its own as you need a minimum of 150mm rigid insulation between the joists / rafters and its best practice to put cosy board over that to reduce heat loss due to poorly cut insulation at the rafter and coldcridge of the rafter itself


on the walls upstairs i also have quinntherm between the joists and it was suggested to me that i removed the quinntherm and place a sheet of fibreglass done along inbetween the joists and then cover this over again with my quinntherm, would this be advisable and would it be benefical? (i have openings left so its possible to get at these areas) thankfully!

I dont really understand this?


The attic at the moment has 100mm of fibre glass i intend up upgrade this but am unsure what to put into it would quinntherm be better than fibreglass here?

Quintherm is a brand name for a highdensity insulation, you need thicker layers of fiberglass to be comparible with the high desity insulation 100mm fiberglass in the attic is not enough, on its own bit i believe you have quintherm between the ceiling joists? On its own you need a min of 16inches of fiberflass, the difficulty with fiberglass is that after time it compacts on itself.. ie it settles and hence does lose its insulation value, the problem with ridid quitherm- its difficult to fit properly, any gaps however small seriously negate the insulation value

Sound insulation - betwen the floors i put fibreglass and some rockwool. i have been advised to put down either blue acustic slabs or a black rubbery type romaterial that comes in roles to help with sound, do you think this would be usefull?

the accoustic insulation and slab are all great however as sound travels better through joisting the rubbery type material you speak of is essential, I always use it, in my case i generally use a cork type material its used for woodenfloors as a soundproof underlay, i cut it into 50mm rolls and use 2 strips ontop of the floor joists and screw down 18mm shuttering ply I prefer and recommend 2 layers of this shutterply, its only an extra few hundred quid but the best money you will spend on the house as you have a far better floor base upstairs

One final question how are you supposted to insualate around dormer windows? most of mine are in bathrooms and since i will be tiling over these i was thinking of adding a 60mm think cosy board sheet over my skimming, then tile away, would this be worthwhile?

is it skimmed here yet? It should have been insulated with the quinntherm insulation behind the slab at the dormer, yes you could do as you suggest by sticking the cosy board onto the existing skimmed wall with bonding compound adhesive and screwing into the joisting (which you need to find behind the slab) as the adhesive on its own isnt suffucent imo

Regards

Brian

Ps - anyfurther questions similar to these- id suggest you post in the construction and planning section as BER section is more for calculations and discussing figures than the practical element of fitting

pologirl

hi snyper,
many many thanks for your reply, this information is very good.

Its best you do both, cosyboard is not sufficent on its own as you need a minimum of 150mm rigid insulation between the joists / rafters and its best practice to put cosy board over that to reduce heat loss due to poorly cut insulation at the rafter and coldcridge of the rafter itself

I have the rigid 4 inch quinntherm installed on the slope but there is just a ordiniary slab over it. its all skimmed inside so is there anyway i can improve the insulation on the slope at this stage? my rafters are 6inches thick.
the piece you say you dont understand ill try and explain it better.
on the dormer walls upstairs i have the four inch quinntherm, i was told this wasnt enough and to either wrap the quinntherm in fibreglass of nail slabs of cosy board in behind the wall, (as this accessable) do u think this would be a good idea? and worthwhile?

Quintherm is a brand name for a highdensity insulation, you need thicker layers of fiberglass to be comparible with the high desity insulation 100mm fiberglass in the attic is not enough, on its own bit i believe you have quintherm between the ceiling joists? On its own you need a min of 16inches of fiberflass, the difficulty with fiberglass is that after time it compacts on itself.. ie it settles and hence does lose its insulation value, the problem with ridid quitherm- its difficult to fit properly, any gaps however small seriously negate the insulation value

on the flat part of the dormer roof i only have 100mm of fibreglass, but i intend to update this to 400, by laying andother 150mm inbetween the joists and 150mm perprndicular to the joists, do you think this is good? or should i use highdensity insulation like quinntherm in the flat part of the attic?

finally, the dormer windows have quinntherm between the joists (around the window) with just a regular foil backed slab over it, it is all skimmed now yes, but what i was thinking of doing was putting up a 60mm slab of cosy board around my dormer windows, and seeing as theses windows are in bathrooms i could just tole directly onto the cosyboard without skimming it again, what do you think of this idea? and do you this its worthwhile?

thanks again for your help,
pologirl

holdfast

Hi

I might be worth getting a professional person out to the house and go through the exact requirements. By the sounds of it there is a lot of work done and money spent unwisely. it would be better to see and advise rather than throw out standard answers. The cost of such a survey will be worth in the long run.

RKQ

Who is certifying Compliance with Building Control / drawing down your mortgage stage payments?

Seek their professional advice.

Are you intending to comply with older standards (due to commencement date and practical completion date?)

You seem to be using alot of Quinn products, why not contact their Technical Sales Department for u-value calculations based on your drawings? - usually free!