Free Loft Insulation - Questions...

[cwhaley]

Our loft insulation (when new in 2001) was 150mm, meaning it would not technically qualify for free loft insulation (maximum is 100mm).

However - I have checked the insulation and it looks to be less than 100mm, with an EPC report done in 2011 backing this up by recording 75mm. I assume it gradually compressed over time. As a result, our energy provided has arranged for a contractor to come and assess whether we qualify in January. Bit of a wait.

Around 20-30% of the loft was boarded out for storage (OSB board screwed to joists) and when this was done, the insulation was simply taken up and chucked to the sides towards the eaves (the loft hatch is dead-centre in the loft). This means that at present we have very ineffective loft insulation that is absent below the boards and piled up in two great heaps either side of the loft hatch.

- Do contractors tend to lift the boards to fit insulation?
- Will they remove the piles of old insulation or flatten out?

Appreciate this may not be answerable! Unfortunately EDF can't tell me and I can't get in touch with the contractor.

Hope somebody has some knowledge

 

[big-all]

no they will lay it on the space you have cleared nothing else
they will move nothing they will alter nothing

 

[Doggit]

Yup, they'll do as little as possible. You'd be best to clear out the scattered insulation, and lift the OSB, but if the do it, they'll lay 100mm between the joists, and then 170mm across them, so the OSB can't go back down unless you install loft legs, and then refit the OSB.

 

[cwhaley]

Thanks - I feared this understandable though given that it's done simply to meet government targets on energy use.

Trouble is I suffer from vertigo and can only really crawl up and slightly around there, embarrassingly so. If they really won't touch anything then I'll try as much as I can before getting somebody in. It's a simple job I know but not when you're pratting around on your hands and knees...

Think I might get the whole loft boarded out properly as well.

 

[Doggit]

Interestingly enough, there was another post recently where the insulation had been completely squashed down, and the unlagged pipes in the loft froze, so there was obviously no heat lost in to the loft. I know you're not good up there, but you may be able to get the insulation people to just put in the 100mm layer, and leave the rest for you to do, and you then screw and glue some 4x2s (upright) onto the joists, and then lay the extra insulation in between and squash it down as you boarded out the loft.

 

[cwhaley]

Doesn't squashing it down impair its performance? I'm not sure if I've seen the post but I assumed when it is squashed down it compresses the air pockets within the insulation?

I might ask them about leaving the additional 170mm for me to do while we figure out raising the boards (good idea with the 4x2s). Will be drafting the brother in for help. I can't imagine them turning down the opportunity for an extra half hour in saved time!

I used to think vertigo was a fear of heights, but when it got worse (sickness, loss of balance) it became a real block for getting jobs done up ladders.

 

[alan333]

Extra loft insulation doesn't save much IMHO. I'll explain...

We have a 4 bed detached house built year 2000, with loft area of about 64m2, which already had 100mm of insulation.

We got cavity wall insulation put in a few years ago, but declined the offer to get an extra 270mm thickness of loft insulation. A few months later I got a letter telling me how great my house now was, but that it could be much better with the extra loft insulation... and I could save UP TO a whopping £9.50 per year!

I reckon that some insulation is much better than none, but lots of insulation is only marginally better than some.

I decided the hassle of lifting the partial flooring and then not having storage space and access to wiring etc outweighed the potential benefits.

 

[cwhaley]

Thanks for the insight and you're not the only one to tell me this, I must admit.

The difference is my house is solid brick and was built when bread and potatoes were still being rationed, whereas your's is a nice modern home with insulated cavity walls built very recently. My loft space has at best 75mm of insulation with some areas having none at all. My parents had it done in their 1904 solid brick house for free in around 2009 (with Mark Group) and the increase in retained heat was certainly noticeable.

Totally understand why some wouldn't get it done and that it only goes part-way in improving the warmth in a house, but for us it's a must (especially when it's free ).

 

[cwhaley]

Thinking about your £9.50 savings point.... I do wonder how they come up with these figures!! My EPC report estimates £950 a year in heating but but we barely used a third of this over the past year. Bizarrely it also recommends cavity insulation despite not having a cavity?!

 

[big-all]

its the laws off deminishing returns
to keep it simple we will call it £100 a year lost through the roof
the first 100mm will save say £80 or 80%
the next 100mm will again save you 80% but now off £20 so £4
the next 75mm will save 60% so a whopping £2.40edit that should be 32p

 

[alan333]

Thinking about your £9.50 savings point....

Not a guaranteed £9.50, merely up to £9.50. Oh how I dream of the expensive foreign holidays I could've been on if only I'd saved that money these past few years lol

 

[cwhaley]

Yes they do get optimistic with those figures lol. Maybe a roof filled entirely with Rockwool and you've saved enough for a few pints in Blackpool.

I must be an eco-warrior on my energy usage versus their estimate...

 

[Diver Fred]

Do be careful - do ensure that you get a clear statement before proceeding that the 'Free' loft insulationis not tied in with free cavity wall insulation.

When I looked into this 'offer' it was only available when combined withcavity wall insulation otherwise it was charged for.

 

[John D v2.0]

64m2

already had 100mm

extra 270mm

save UP TO a whopping £9.50 per year!

It does sound silly so I did some calculations
100mm would be 0.41u
270 would be 0.18u
Saving 0.23
64m2 gives 15w per degree
Assume around 1800 degree days a year or around 5 degrees average
75w average loss
Gas is 3p a kwh
So I make that more like 20 pounds a year.
But if you assume the house is only heated 8 hours a day...!

 

[big-all]

It does sound silly so I did some calculations
100mm would be 0.41u
270 would be 0.18u
Saving 0.23
64m2 gives 15w per degree
Assume around 1800 degree days a year or around 5 degrees average
75w average loss
Gas is 3p a kwh
So I make that more like 20 pounds a year.
But if you assume the house is only heated 8 hours a day...!

much more important than the monetary saving is the cost off extra materials both insulation and extra timber to accommodate the extra bulk along with the carbon footprint to make deliver and install them
also the loss of vital storage space when people are often struggling to find storage room