Best insulation to complete a partially insulated and boarded loft (with some awkward areas)

[JimDogweed]

Hi. This is my first post here and I was hoping for some advice.

I've recently moved in to a new house, built around 1900-1910. It's a terraced house, and we're on the corner.

One of the previous owners has done what I would describe as a "partial" loft conversion. It's not a "room" - it has a pull down ladder, but does have a couple of Velux windows.

The loft is split, with around half of it boarded with plastered walls, etc. There seems to be insulation under the floor, and behind the walls they've created.

The other half is separated by a wall and small door (not draught proofed ). However, this area is only partially boarded. Again, there does seem to be insulation under the boarded areas.

Now the not so good part - There's a good sized area in the corner isn't insulated at all. Also, where they have made walls in the main are, they have added insulation to the back of these walls, but it stops there. Meaning there's a gap without insulation around the edge of around 1m or so - this area is also very small/awkward, so I don't think I could fully get to it.

I can only assume there is some insulation between the plastered ceiling and the actual roof.

The mess/rubble in the pictures seems to be what was left behind when the roof was replaced a few years back.

I'm looking for advice on the best approach. For example, what kind of insulation would be best to complete what's been done already? I'm mainly concerned about the edge area (behind the walls) which will be hard to reach. I'd prefer not to have to rip out what's been done.

Thanks in advance.

Images below...

 

[foxhole]

Easy enough to roll out some rock wool into the edge of the roof, you don’t need full access as you can use a broom handle at a distance to unroll and move around .

 

[JimDogweed]

Easy enough to roll out some rock wool into the edge of the roof, you don’t need full access as you can use a broom handle at a distance to unroll and move around .

I think I could do that for some it it.

With this part mainly, below...

View attachment 186582

It goes a little further than you can see in the picture so I may not reach all the way along - it's probably going to be quite difficult to get in and remove the rubble from when the roof was done too. Would there be any issues in laying the insulation over the top of what I'm unable to remove?

 

[foxhole]

Not ideal , remove what you can then stuff in the insulation.[one of those times you could make use of a small child]

 

[JimDogweed]

Just wanted to bump this post, since the weather is starting to get cold, and need to explore some proper solutions. I've also been able to take a proper look and all isn't as I first thought.

Basically, it looks like there is no floor level insulation in the loft at all - it looks like there is none under any of the floor/board areas, on both sides of the loft.

The "nicer" side with plastered/painted walls looks to have an (old) layer of insulation that goes over the top and down the sides. The big issue is that the sides stop about 1m from the edge of the house. Also, this gap is not accessible. I can't see behind it on of the sides - if it's anything like what you can see in the last picture above, it'll be filled with rubble, wood, and other crap!

Would ideally like a solution that will minimise damage and ripping up flooring/boarding there. Not sure what the best thing to do - I feel if I address part of it, it's pointless as I can't get the full benefit.

Any more advice?

 

[cdbe]

Bitty insulation is not ideal but better than nothing at all - if this is all you want then just cover as many vertical and horizontal areas with rockwool or celotex (more expensive but better performance). Bear in mind that if you insulate the rafters (sloped parts) you need to ensure that the roof is ventilated (50mm air gap between felt and insulation, and vents at top and bottom of slope to provide cross ventilation).

I would be investigating the loft ceiling to ensure it is ventilated as above and not just stuffed with rockwool (you need to have a poke around above those purlins).

To get to modern standards it could be a full strip out - hardly worth it unless the room is being occupied.

Another option to consider, particularly if the house is a doer upper, is underboarding the ceilings in the rooms below (100mm celotex with plasterboard below).

 

[JimDogweed]

Thanks, that's useful and interesting.

Another option to consider, particularly if the house is a doer upper, is underboarding the ceilings in the rooms below (100mm celotex with plasterboard below).

Unfortunately not, and not something we'd want to do now - the rooms below have some original features on the ceiling too, which we'd like to keep as long as possible.

To get to modern standards it could be a full strip out - hardly worth it unless the room is being occupied.

Agreed!

I would be investigating the loft ceiling to ensure it is ventilated as above and not just stuffed with rockwool (you need to have a poke around above those purlins).

I've had a look around today and from what I can tell, there is a gap - there is also some clearance above the "ceiling" part as well.

Bitty insulation is not ideal but better than nothing at all - if this is all you want then just cover as many vertical and horizontal areas with rockwool or celotex (more expensive but better performance). Bear in mind that if you insulate the rafters (sloped parts) you need to ensure that the roof is ventilated (50mm air gap between felt and insulation, and vents at top and bottom of slope to provide cross ventilation).

I think I'm going to go for the bitty option... Definitely stuffing it where I can... I may be able to lift the flooring in the non-plastered part to en extent so that should help.

Is Rockwool recommended over Earthwool or something - Rockwool comes in slabs, yeah?

I probably wouldn't do between the rafters - I did think about using super quilt foil but I wasn't sure how much it would be worth it (since I can't do it all). But if I staple to the rafter, that would leave a gap.

 

[cdbe]

Is Rockwool recommended over Earthwool or something - Rockwool comes in slabs, yeah?

It's just a price/performance/ease of installation equation.