Loft insulation

[Leafster]

Boring topic I know, but with the energy situation it's been mentioned frequently on a number of threads recently.

I thought it might be a good idea to have a dedicated thread to it. I did search for earlier threads but the last one was in 2008!

My loft has some insulation and was partially boarded out by a previous owner. It also looks like they had plans to lay more insulation in the loft as there were several unused rolls up there. I've used most of these on areas which weren't boarded but even so I doubt it's anywhere near the 270mm to 300mm which is recommended.

So... I have a number of questions.

I can buy more insulation to lay on top of the existing stuff but should I be concerned about wiring over-heating and, if so, what should I do about it? I already have cages over the ceiling lights which are recessed into the roof space.

The area which is boarded out is laid directly on the joists but there appears to be very little insulation under the boards or space to add more. Has anyone used something like loft legs (Raise Loft Floor Above Insulation | London, UK | Loft Leg) to increase the space for insulation?

If you've boarded out the loft and raised the height so you can get sufficient insulation underneath how did you do it? Would it be relatively easy with someone with 'limited' DIY skills? I'm not planning on doing it all in one go so not too worried if it takes me a while but I might need more tools.

Is there such a thing as insulated boards if I wanted to extend the area that's boarded out?

Also, which type if insulation gives you the best bang for your buck and is there any problem with mixing different types.

Feel free to use this thread to ask your own questions.

 

[StoneRoad]

This is all my opinions - I'm not an expert professional in this field, more of an interested amateur / DIY person.

Yes, I think that there are insulated boards. I seem to remember seeing such things in one of the DIY sheds a while ago.

Also, some of the foil coated foam boards are way, way easier to fit than the rolls of fibres. Assuming your joists are at the right separation
{and I would expect them to give better insulation, but that's without checking the current figures - and it doesn't compact down like rockwool can do over time}.

You do need enough ventilation to prevent problems with condensation & overheating light fittings ...

Currently our loft space has a mixture of very old rockwool, modern rockwool and foam boards. Plus, a lot of it is occupied by a loft conversion and some of the rest has water tanks or is boarded out for storage.
I'm planning to fit thin foam boards - fire-proof ones ! - to the underside of the roof, as well as re-arrange the storage and boarded out areas to incorporate more insulation etc. The head room isn't that good in some areas - the roof frame is actually steel, not wood

 

[two sheds]

I’ve got 180 mm insulation, should upgrade to 300mm it but there’s not much headroom up there. I should check for installers. I also saw a photo of someone installing insulating boards between the rafters that could be tempting for while they’re up there,

 

[Leafster]

I've heard conflicting information about putting insulation between the rafters/underside of the roof. It seems to depend on the construction of your roof but apparently it's often difficult to maintain good airflow over the roof timbers which can cause them to rot.

My roof is made of rafters with sarking over the top and then the tiles laid on this. It may have some form of weather-proofing in between the sarking and the tiles but it still has the original tiles from 1930 so no-one really knows. I gather the wooden sarking relies on good airflow on the underside to keep it from getting/staying damp.

 

[two sheds]

Yes from what I could see they were using rolls/panels and leaving space between rafters. Not sure I fancy either mineral wool, Kingspan or Celotex though. Can't remember what's between my rafters but black plastic I think.

 

[two sheds]

Not sure whether it'd be worth topping up to 300mm in the loft if the insulation on the walls (insulating wallpaper) isn't up to the same spec. Am tempted to rent an infra-red imager in the next cold snap (shared with some neighbours) and see what the relative temperatures of the walls/ceilings are.

 

[Leafster]

Not sure whether it'd be worth topping up to 300mm in the loft if the insulation on the walls (insulating wallpaper) isn't up to the same spec. Am tempted to rent an infra-red imager in the next cold snap (shared with some neighbours) and see what the relative temperatures of the walls/ceilings are.

I've read discussions where they've said it's not worth increasing one type of insulation if the rest of the property is poorly insulated but if you're slowly upgrading your insulation there are going to be times when it's inevitable.

I think using an heat imager is probably a very good way of identifying the worst heat losses so you can focus on them first. I keep thinking of getting someone in to assess my place but the cost is putting me off.

 

[platinumsage]

Ours is about 100mm with some bits boarded over. I decided it wasn’t worth upping it all to 270mm and instead just filled in a few obvious gaps.

 

[two sheds]

I'm thinking of something like this (chosen at random) Thermal Imaging Camera Hire for two or three days for when we get a cold snap.

 

[Elpenor]

I’ve not been in my loft yet since moving in July so have no idea. The survey referred to there being some; and the loft being partially boarded, also some electric cables covered in insulation which seems to be a bit of a no-no.

Must admit I’m not that keen on climbing up the ladder when no one else is in the house. Maybe a task for when I next get a visitor, but it’s hardly a sociable thing to do

 

[Leafster]

I’ve not been in my loft yet since moving in July so have no idea. The survey referred to there being some; and the loft being partially boarded, also some electric cables covered in insulation which seems to be a bit of a no-no.

Must admit I’m not that keen on climbing up the ladder when no one else is in the house. Maybe a task for when I next get a visitor, but it’s hardly a sociable thing to do

What did the EPC say when you bought the place? That might have a bit more detail about the amount of loft insulation.