Cellulose insulation - Ouaté de cellulose

[nomoss]

Our "new" house was empty for some years before we bought it. We decided to lift and remove all the floorboards in the roof space, as they were woodworm attacked and very dirty, as the chimney had evidently leaked badly at some time and covered all in soot.

On removing the boards we found much evidence of rats living in the fibreglass insulation between the floor and the ceilings below, so we removed all the fibreglass to the déchetterie, together with most of the ceilings, which were lambris, and pretty nasty too.

We now have new plasterboard ceilings and are considering putting 25cm of cellulose insulation above them before we floor the roof space again.

Does any one have long-term experience of this material, particularly regarding its attactiveness to rodents?

We are principally concerned that rats may return, and worried they may like the cellulose even better than fibreglass insulation. All access paths to the roof space have been closed off, but the house has cavity walls through which they might find a route.

I have read that borate salts (15 to 20% depending on who one reads) are added as a fire retardant, and that these also control mould, insects and rodents. Sounds just a bit too convenient that such a cheap and easy additive can confer these properties.

I accept the fire and mould retardant bit, but have found no convincing evidence regarding insects and rodents.

I know that borax will kill cockroaches and other self-grooming insects, but only after some time, and if consumed in sufficient quantity, but have never heard claims of it's being a rodent repellent except in this context.

I would appreciate any information; I'm not about to improve the house for the rats' benefit.

[Théière]

Rats can live in sewers so a little bit of borax isn't going to hurt them.

Rodents can and do live in rock wool, glass fibre, pu foams, PIR foam, polystyrene, sheep's wool and cellulose. In fact most places you don't want them and any company that writes anything different is talking bollix.

Like us they don't like chewing metal such as chicken wire and stainless steel etc so putting that into the eves first may help.

Using a reflecting material in your roof will make an enormous difference to keeping it cool in summer and if you have a reflecting layer to the inside keeping the warmth in in winter. Backing that up with more insulation will also help. You need to maintain an air gap between the reflective film, this is important.

 

[nomoss]

Thanks, Théière, you confirm what I rather suspected.

The roof has been completely replaced and the eaves are sealed with cement. The new roof has mechanical canal tiles laid on OSB and glued down, so is also well sealed.

We have sealed up, also with cement, all the holes which were hacked through the loft walls by the artisans who installed wiring and central heating pipes in a 1970's "renovation", as well as the holes bashed through from outside by the installers of the air conditioning.

As the roof area is vast, covering the adjacent shop premises as well as the house, I really want to insulate just the (single storey) house ceilings, rather than the entire roof.

We intend renting out the shop eventually. The ceilings are thick reinforced concrete, as it used to stock and sell guns and ammunition, so it should be fairly well insulated. If the future tenants have a problem I'll grant them roof access to insulate it themselves.

Now I have some confirmation of my doubts about claims for cellulose insulation I will probably still use it, but take great precautions to keep the rodents out.

I intend to seal all the OSB flooring in the roof space to the walls with cement, and check the floors periodically for any rodent activity. The old floors were sealed, but the imbeciles who rewired just chopped holes anywhere and everywhere to get through them, leaving a really nice run for the rats.

Coming from a family of builders, and having myself had an air conditioning company in Spain, I am totally amazed that anyone could be stupid enough to pay good money for the kind of inept work which has been carried out on this house over many years.

The divorced lady who owned it previously was a leading light in the local Chamber of Commerce..... Presumably she paid local "artisans"on the black for work on the house - she evidently got what she paid for, or they did what they felt the payment was worth.  None of the people she mentioned even admit to working on the house - at least their wives, who run their shops, don't [Www]

My "local" builder is from Paris. he doesn't have a very high opinion of skills in the area either [:D]. He's not cheap, nor expensive, just does an honest, good job.

[Théière]

In our house the 5ft grass snake that lives under the hot water tank keeps the rodent population down [:-))]

[BIG MAC]

In your house the five foot grass snake is finding enough grub to  stay in a living and prosper...Therefore I suspect that the rate of rodent production may exceed the snake's dietary needs