Attic Insulation Question

Tidyweb

I have a fairly new house.

The attic is full of some type of grey blow-in insulation.

I am currently covering it with 200mm of regular roll out yellow insulation rolls.

Does this grey stuff have much insulation properites. There is about 100mm in place at the moment.

Thanks

Tidyweb

any ideas

BryanF

Tidyweb
fairly new? must be pre 05 building regulations? or your builders/specifier cut corners on insulation..
If I was you I would have added more of the same insulation - from what you describe its probably cellulose and would have similar thermal properties as the mineral wool your installing. if its already done them it will probably be ok, my concern in alternating insulation types is where the due point might be which is relevant if the standard of Vapour control isn't great allowing moisture migration from below to condense in the insulation zone
don't forget to leave to 2inch space between the felt and eaves - presuming that's how the roof is vented.

Tidyweb

Good points I never though of that.

It is messy old stuff and I dont want to add more of it. It is only as high as the top of the joists. At least the roll out stuff helps keep the dust down a bit.

It would have been impossible to remove it all as it is a big house. The house was built in about 2006.

What should it have been, anymore would have been higher than the joists and very messy.

Can you put too much insulation in?

aujopimur

Use a brush or a rake to get the blow in stuff into decent coverage between the joists, then use 100mm. roll to fill the gaps.
Top up with 200mmm.

BryanF

Tidyweb wrote: »

Can you put too much insulation in?

no, but deal with your pipes and water-tanks

Tidyweb

yea, I am just covering the with 200mm roll, so all the joists will be covered by 200mm roll.

Kinda ruins it for storage or walking around.

Do people with alot of insulation not use the attic for storage~?

BryanF

ye of course, build a plat-from in timber and ply or locally put up rigid insulation with ply on top

farbe

I am putting additional insulation into my attic to bring it up to the standard for the seai grant. This is an easy access walk-in attic in a dormer bungalow and very useful storage area. To protect the new insulation and to retain some storage area, I will now have to build up the joists and lay sheets of ply on top depending on the storage area required. Is it ok just to lay the ply down without screws.
Another option I was given by contractor is to lay down t/g chip boards with 100mm eps insulation 4 x 1.50 ft. Is this the same as osb board?
The storage is required for christmas tree etc, luggage and general household. I would appreciate any recomendations and advise.

DoneDL

If you get 7x1 inch sawn and make a frame you can insulate the frame then fix 1/2 ply to this as a storage platform.

farbe

I am putting additional insulation into my attic to bring it up to the standard for the seai grant. This is an easy access walk-in attic in a dormer bungalow and very useful storage area. To protect the new insulation and to retain some storage area, I will now have to build up the joists and lay sheets of ply on top depending on the storage area required. Is it ok just to lay the ply down without screws.
Another option I was given by contractor is to lay down t/g chip boards with 100mm eps insulation 4 x 1.50 ft. Is this the same as osb board?
The storage is required for christmas tree etc, luggage and general household. I would appreciate any recomendations and advise.

John mac

heres one from earlier.
http://www.boards.ie/vbulletin/showthread.php?p=54886772

I did mine like this.

farbe

Thanks for all the help which I found very useful. Very pleased with completed storgage area.. Is there much additional benefit to flooring an entire attic after increasing insulation to 300 mm between joists or would this merely bring minimal benefit for the cost involved.

BryanF

farbe wrote: »

Thanks for all the help which I found very useful. Very pleased with completed storgage area.. Is there much additional benefit to flooring an entire attic after increasing insulation to 300 mm between joists or would this merely bring minimal benefit for the cost involved.

what are you asking here? cost V reduction of heat loss due to laid floor - very little, no worth it : cost V increased value selling property - you decide

farbe

Thanks again Bryan F. Yes, tha's exactly what I wanted clarified i.e. cost v heat loss - remaining attic area is only suitable for storage due to height.