Leave or remove this attic insulation (pic)

edanto

I have some old attic insulation up there, but it doesn't really seem to be doing much and I'm going to put down a new layer of fibreglass.

I don't know if the insulation up there is effective at all, or just in the way. Perhaps these pictures won't help much, but it anyone could help me decide I'd be grateful.

I think the U value of insulation depends on how much air is trapped in the insulation and this stuff doesn't have much spring in it, seems more dusty than anything else.





So, take it down or leave it up?

Carlow52

I see no reason to move it unless it is toxic.

Why fg?
why not more loose? much easier to do....

gsxr1

I have to agree. It would only add to the insulation .

BryanF

is it damp????
is it solid
how long is it in place/ is it the same as when it went in

describe.. or preferably get a professional to check

edanto

Thanks guys, appreciate the advice.

@ Bryan, no its not damp at all, bone dry. No idea when it went in, nor if its state has changed since then. Solid.... well it's a broken dusty type of material, wouldn't describe it as solid.

meercat

insulate over it
have seen it done lots of times before
the more insulation the better
you need to leave some ventilation from soffit to allow air flow though

edanto

Understand that, thanks. Rolls arriving tomorrow mornin.

meercat

edanto wrote: »

Understand that, thanks. Rolls arriving tomorrow mornin.

post pics when done thanks

slimjimmc

Old stuff looks like cellulose fibre insulation. Keep it.

Enjoy the extra warmth in the rooms below but don't forget to beef up the lagging around pipes and the cold water storage tank. The extra attic insulation you're putting down will reduce the temperature in the attic space since (hopefully) less heat will be leaking up from below.

DanWall

Looks like rockwool that is blown in

edanto

Thanks for the advice guys



Got the first layer down today and a little bit of the flooring (using the insulated board). No gaps. Feels much warmer already in the house, happy days.

Next week will be putting down another layer in the places that I'm not flooring, for super cosyness.

I left plenty of space for air to flow at the edges (did someone say they're soffits?) and wrapped the tank real well.



One mistake I made was not wearing eye protection - very stupid of me. And there was me thinking I was all sorted with my big white suit and dust masks. Hopefully all will be well in the morning, but sure if I have eye problems I'll get it sorted.

edanto

No problems with the eyes, all good.

I'll be sure and get some eye protection before putting down the next layer... but there won't be any cutting with that layer really since it's going perpendicular to the other one.

Thanks for all the advice.

meercat

looking good:D

gsxr1

great job. You will really feel the difference this winter.

edanto

It's bleedin brilliant! Heat has been off for the past two hours and the house is still warm. Love it!

Used to be the house would be cold 10 minutes after the heat went off... loving this insulation. And there's still another layer to go up :-)

Rancid

edanto wrote: »

I have some old attic insulation up there, but it doesn't really seem to be doing much and I'm going to put down a new layer of fibreglass.

I don't know if the insulation up there is effective at all, or just in the way. Perhaps these pictures won't help much, but it anyone could help me decide I'd be grateful.

I think the U value of insulation depends on how much air is trapped in the insulation and this stuff doesn't have much spring in it, seems more dusty than anything else.




So, take it down or leave it up?

The stuff in that pic is *exactly* what I have in my attic and I wondered if it was safe to leave it there, it is so loose and fluffy that touching it all causes it to blow around like dust.

Any idea what it is called?

I'll be insulating the attic properly in the new year and had considered removing all of that stuff and starting from scratch.

edanto

Well if you're going by this thread, leave it up there and insulate over it.

If you're Dublin based, Brooks have a deal at the moment where 7m2 of 150 mm is e15, and they deliver.

Only takes a day to get done what I have in the pics above. Wish I'd done it as soon as I moved in months ago.

tom1ie

edanto wrote: »

Well if you're going by this thread, leave it up there and insulate over it.

If you're Dublin based, Brooks have a deal at the moment where 7m2 of 150 mm is e15, and they deliver.

Only takes a day to get done what I have in the pics above. Wish I'd done it as soon as I moved in months ago.

Hi edanto Great job! What is the name of that insulation your putting up and do you know what the u value is? also how many rolls did you buy?

derealbadger

edanto wrote: »

No problems with the eyes, all good.

I'll be sure and get some eye protection before putting down the next layer... but there won't be any cutting with that layer really since it's going perpendicular to the other one.

Thanks for all the advice.

Also try pitting baby powder all over yourself before getting suited up stops the fibers from sticking is a class job

edanto

[/QUOTE] What is the name of that insulation your putting up and do you know what the u value is? also how many rolls did you buy?[/Quote]

Best if you call Brooks, they have it on special, 14.90 each roll for the 150mm. Not sure what the u value is off hand.

slowburner

Hope I'm not butting in.
Can anyone give advice on the amount of space which needs to be left between the insulation and the roofing felt at the soffit/fascia end of the joists?
Presumably, the idea is to allow the circulation of fresh air to prevent roof timbers from rotting?
If the gaps were closed with insulation - would the timbers really rot?
Also, what is the current thinking on insulating a cold roof i.e. between the rafters and up to the felt?

edanto

Not butting in, no worries. I heard about 2 inches was a good gap.

I wasn't neurotic about getting an even 2 inches everywhere, the main consideration was air circulation and I could feel the wind coming in when there was just a gap of an inch at the back of house soffits.

Others with more experience might have a better answer!

Not entirely sure what you're asking about in the second part, could you explain what options you're considering?

BryanF

slowburner wrote: »

Hope I'm not butting in.

1. Can anyone give advice on the amount of space which needs to be left between the insulation
2. and the roofing felt at the soffit/fascia end of the joists?
3. Presumably, the idea is to allow the circulation of fresh air to prevent roof timbers from rotting?
4. If the gaps were closed with insulation - would the timbers really rot?
5. Also, what is the current thinking on insulating a cold roof i.e. between the rafters and up to the felt?

i presuming this is existing? if its new then you can use breathable felt and double batten above meaning you don't need to consider ventilation

1. minimum of 50mm which has always been the case- this has always been the case - see here p28
2. same as 1. this is of the utmost importance, i have recently been specifying rigid pvc 50x200 cut to about 1200 sections for retro-fitting situations, there are proprietary ones on the market also.
3. yes and to hep remove miosture that comes up from the house in warm air and condenses on the felt barrier - which in the past has often been a bitumen type material, that is not breathable, now their more like a gore-tex..
4. yes, even within a year, there can be problems + the moisture often comes back down to visit, starting on your ceiling plasterboard
5. as much as possible see here p67 & here p17 my preference is for mineral, hemp or wool batts, as they can absorb and release a certain amount of moisture unlike the EPS/PIR poly based products, don't forget the vapour barrier on the inside..

slowburner

Great, clear post. Many thanks.

Yep it's an existing building. The roofing felt is not the breathable stuff and it's beginning to show its age.
What would you think of retrofitting a new breather membrane underneath and insulating up to it?

BryanF

slowburner wrote: »

Great, clear post. Many thanks.

Yep it's an existing building. The roofing felt is not the breathable stuff and it's beginning to show its age.
What would you think of retrofitting a new breather membrane underneath and insulating up to it?

the breather membrane must have the joists on the inside of it,(as per the details on the information i gave you) otherwise your roof timbers will be exposed to the elements, albeit with the tiles/slates in the way..

so if your saying you would remove and relay/replace the slates and re-do the roof installing VB, insulation and breather membrane then yeah, go for it,

I'm doing one like this is the spring, hopefully to near passive standards, (ill probably be going for a gutex type wood fibre board over the rafters thats acts like a breather membrane but also has insulating properties)

otherwise keep the ventilation, and maybe loose a little of the room height presuming you can afford to do that

(and before anyone comes on talking about foil based skinny insulations, there only a reflective product and need insulation with them!!! and are not breathable, so they may cause their own set of problems on an old house)