Tuesday, 8 November 2011

Insulating a Flat Roof...

... From the Inside!

Having replaced the flat roof above our kitchen, we've now ripped down the internal ceiling - sounds a bit of a weird way of doing things, but the weather wasn't in our favour when the roof was being done and we couldn't do without the kitchen at the time, nor could we risk water into the electrics. Now, however, we are left with a dilemma - what type of insulation should we use?

The insulation will need to be fitted from the inside before the new ceiling goes up, so this does make things a little bit more complicated: the insulation needs to be held in place until the new plasterboard gets fixed and, just to complicate things more, these jobs may not be possible to do on the same day.

Insulation is really important in as far as holding in the heat during our freezing Scottish winters and the recent weather has done nothing to help things along. Now that the frost has arrived, we need to work quickly to beat the big freeze that is bound to arrive soon.

Insulation, insulation, insulation... slabs, butts, rolls, Celotex, Kingspan, Rockwool, Thermafleece, EcoTherm, Space Blanket... ? I don't really want glass fibre or cheap and nasty, but costs for anything else are ridiculous for such an essential component of our renovation project! And what's worse is the fact that this is just the first room! We have no insulation at all at the moment.

Keep in mind that this is for a kitchen, so there will be extra heat generated from cooking that I'd prefer not to lose straight up through a flat roof. There will also be steam, which could cause condensation if we don't do the job right.

Whatever I choose, it will probably be fitted above foil-backed plasterboard and then decorated. We probably won't plaster the ceiling, prefering to employ a more frugal, Scottish process known as 'Ames Taping', then simply decorating over the top.

I haven't decided on any interior decor, yet. That's way down the list of priorities. The immediate problem is settling on what type of insulation to use, when I would prefer NOT to use the cheap and nasty glass fibre variety.

This blog post is now open for debate and comment... what type of insulation do you think would be the best to suit our purpose?

From an ecological point of view, I would love to use the environmentally friendly sheep wool, like Thermafleece.

For ease of fitting, thermal boards such as Kingspan or Celotex would be an obvious choice.

All of the above are expensive in comparison to the 'cheap and nasty' subsidised rolls of insulation that are currently available at 'buy one, get 3 free', IF you live anywhere near a stockist. We don't! That would be a huge saving, but would I be happy knowing that's what's up there when we're planning on being here for the longterm with the kitchen being the busiest room in the house?

From a financial point of view, I can have insulation board delivered, probably free, from our local(ish) builders' merchants, whereas the sheep wool variety is being quoted at £60+ JUST FOR DELIVERY!

The boards are far easier to work with in our situation, what with them being installed on the underside of the ceiling, cut to fit and they should stay in place while fitting the plasterboard. It makes me wonder if 100mm polystyrene would be simpler to use.

Why is sheep wool so expensive when farmers are constantly complaining that they're only getting about 50p per fleece at shearing time?

Are the terms 'green' and 'eco-friendly' just new-age speak for 'expensive'?

Why is it so impossible to be green AND frugal?

Your recommendations or feedback on this matter would be greatly appreciated. The job has to be done soon, the kitchen renovation 'savings pot' is about to be emptied and I don't really want to regret my choice a few winters down the line.

If any insulation supplier would like to sponsor the Frugaldom kitchen roof project, I'll happily dedicate this post to your company and ensure that all SEO tactics are employed to your full advantage! :)

NYK Media


  1. I would go for the cheapest insulation option. I have even heard of old denim and old newspapers being treated with a fire retardant. Foil backed plasterboard is going to reflect the heat back anyway.

    I rough plastered my house with just a wheelbarrow (no mixer) trowel and a float. It only cost me 20 Euros to plaster (artex)my ceiling), with some pva glue and a bag of skim plaster - very Spanish restaurant!

  2. Sounds plausible, Dave, but this needs to be as hassle free as possible, owing to the fact that the small hallway and kitchen need to be in use. We only need about 18 sq metres. I'm off to a LETS meting now, perhaps someone in town will have a few spare rolls lying about the place? And I'll pop into the builders' merchants for some quotes including delivery.

    I can't do mixing or plastering - I'd break a nail! LOL

  3. My other half is an architect and reckons this one will be very good:


    If you select RW5 or RW6, that should be hassle free and good quality.


  4. Thanks again, I'll take a look at the Rockwool ad compare it with the other insulation boards before deciding.

    Estimate now in for replacing the kitchen window and there's scope to save over £100. Trouble is, we're working on a like-for-like basis, owing to the property being Listed, so the savings, like the grants, aren't applicable to us.

    Best get more writing done, I'm a few pounds short of a window and then there's the fitting to be factored into the equation. Next challenge will be the door and frame to be renewed before Christmas. Doing it this way still beats borrowing money to get it all done at the same time, though! :)

    Christmas still not looking too sparse, though, as the Amazon vouchers are still ready and waiting for spending.

  5. Please do not post spam links to my blog - they get deleted, you don't get paid, you are wasting your time here!


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