How long does loft insulation last?

[Monty_jon]

I’ve noticed that my loft's insulation looks very dirty and flat. It was done in the mid-90s

Would it be a benefit if I replaced the old stuff?

 

[JohnD]

It doesn't wear out, but old stuff was thin.

The old yellow fibreglass is very bad for shedding irritant dust and fibres. If, like me, you are badly affected by it, I would don a good mask and bag it up, clean up the loft with a canister vac, and replace with (much thicker) modern mineral wool treated with Ecose.

Unfelted lofts are also very dirty because they accumulate dust and grit. Old ones are worst because they may have many years of pollution from coal and wood fires and factory chimneys.

Once it is clean enough to work in, consider improving the lighting (very easy in a loft where you can see the cables, and often some junction boxes, from the rooms below. Unless the joists are very deep, you will benefit from adding counterbattens, which you can lay a second layer of insulation between, and boards on top to walk on safely. I used decking timbers, which are cheap, readily available, and pre-treated with preservative. When screwed down (don't use nails) this adds rigidity and spreads the load.

If it gets dirty again, it is very easy to hoover a flat boarded floor. If your roof is renewed, using felt or modern breathing membrane, it will not get dirty.

 

[cdbe]

Latest phone scam doing the rounds is - "the Government recommends that your loft insulation is inspected every two or three years, and we can provide this service to you". I didn't wait long enough to see what they wanted to charge for this nonsense.

 

[Monty_jon]

I was going to get a company to do it as I’m too old be crawling around in my loft

But as you state, I’d never use a cold caller!