Loft boarding project started

danlightbulb · 27 May 2025 at 21:47

Started removing some layers of insulation this evening to see what I'm working with.

Ceiling joists are 1.75" x 2.5" approx. 43mm x 65mm. Possibly too small for loft legs so I'm looking at cross battening or adding a new 8x2 floor structure.

Already filled 12 bin bags of old insulation and hardly made a dent. Don't want to remove all of it, just need to remove enough that I can board a section and move insulation from another area into the completed section so I can move around the loft that way.

Existing insulation is not itchy on my skin so it's probably relatively modern coated stuff.

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Fireskull · 28 May 2025 at 09:40

Yeah that existing stuff looks like rockwool, which is good stuff.

danlightbulb · 28 May 2025 at 10:57

Fireskull said:
Yeah that existing stuff looks like rockwool, which is good stuff.

It was difficult to get up, didn't really roll up well so I ended up just tearing it into chucks and stuffing it into the bin bags. Probably makes what I've bagged up non-reusable.

The layer underneath is very compressed. In places there is a different white material encased in plastic bag outer.

danlightbulb · 28 May 2025 at 12:34

Do you think I should stick to Rockwool, or is the cheaper glass fibre (Knauf) just as good?

Rockwool is double the price of Knauf.

Mason- · 28 May 2025 at 13:27

Not sure why you removed the layer between the joists. Fair enough to remove the top layer so you can see the timbers.

In terms of the strength of the timbers, what are you going to store up there? As the boards will run perpendicular to the joists - you will be spreading the load across multiple. If you stick 8x2 over the top you're just adding more weight unless the 8x2 are resting on something load bearing either end.

Tbh if it's just standard stuff you are storing up there, suitcases, a few boxes, paint tins etc. I would just stick loft legs down and crack on. It's supported you - no idea how heavy you are but probs between 80-100kg, and you were probably spreading your weight over 2 joists as you removed insulation? It's not like you're putting a bath tub up there or storing a car in the loft.

danlightbulb · 28 May 2025 at 13:59

Mason- said:
Not sure why you removed the layer between the joists. Fair enough to remove the top layer so you can see the timbers.

In terms of the strength of the timbers, what are you going to store up there? As the boards will run perpendicular to the joists - you will be spreading the load across multiple. If you stick 8x2 over the top you're just adding more weight unless the 8x2 are resting on something load bearing either end.

Tbh if it's just standard stuff you are storing up there, suitcases, a few boxes, paint tins etc. I would just stick loft legs down and crack on. It's supported you - no idea how heavy you are but probs between 80-100kg, and you were probably spreading your weight over 2 joists as you removed insulation? It's not like you're putting a bath tub up there or storing a car in the loft.

I wanted to expose the ceiling to check it's condition, and also expose the internal brick supporting walls which go to the loft floor. Plus after removing the top layer the bottom layer was a mix of Rockwool and some plastic wrapped stuff which I didn't want to keep (condensation trap).

Will be storing Xmas decs, camping gear, diy bits and pieces, suitcases, boxes of books. Yeah not too heavy but there's a lot of it.

I haven't treaded on the middle of the joists yet, I've been working from an area over a brick internal supporting wall.

So yeah I could support additional joists off a ledger board attached to the party wall and resting on the various internal brick supporting walls.

Mason- · 28 May 2025 at 14:20

Fair enough - that's a lot of work for loft storage. By the way if you're terraced or semi detached and you plan to support a new timber on a party wall you should get a party wall agreement.

Mysterae_ · 28 May 2025 at 14:50

Good luck, getting started is often the hardest part.

You've probably seen my thread where I've recently completed my loft, you'll soon feel like Tarzan sometimes swinging between the joists!

danlightbulb · 28 May 2025 at 14:52

Mysterae_ said:
Good luck, getting started is often the hardest part.

You've probably seen my thread where I've recently completed my loft, you'll soon feel like Tarzan sometimes swinging between the joists!

Yes Im particularly interested in your insulated loft hatch solution and will come back to ask more on that when I get to that stage.

What type of insulation did you use?

Fireskull · 28 May 2025 at 14:55

danlightbulb said:
Do you think I should stick to Rockwool, or is the cheaper glass fibre (Knauf) just as good?

Rockwool is double the price of Knauf.

I personally have 100mm rockwool between the joists, but my ceiling joists are 95mm, and then I have 170mm rolls of the Knauf stuff on top running in the opposite direction to the joists.

Mysterae_ · 28 May 2025 at 15:05

danlightbulb said:
Yes Im particularly interested in your insulated loft hatch solution and will come back to ask more on that when I get to that stage.

What type of insulation did you use?

No problem, the loft hatch solution has worked really well.

For the lift hatch insulation I used 100mm Recticel eurothane GP insulation board and Knauff loft roll 44 combi cut for the rest of the loft.

danlightbulb · 29 May 2025 at 14:00

The existing product is 170mm Rockwool, although it's not 170mm anymore more like 120mm.

I found packaging with a label attached in the loft. Unfortunately no date on it, was hoping to get an indication how long ago it was done.

danlightbulb · 29 May 2025 at 16:18

Another strip light installed into the loft so now have two of these which has improved the coverage.

Something to note on these lights is that they are daisy chainable. However there is no earth terminal so the cable after the first light has no earth protection. Poor design.

danlightbulb · 29 May 2025 at 17:57

More area exposed.

Another reason I wanted to get more insulation up is to get to the old chimney area which I expected to be full of rubble and it is.

Now I can see what I have to work with. There is a thick beam over to the far side and a supporting wall nearest to me. Perfect I think for bridging some new framing over.

My plan (please comment if you think its ok or needs refinement):

Ok so the far side timber is 7x3 ish, sitting on top of the 2.5" ceiling joists so I have about 240mm ish of height. I think that will be ok for insulation depth, not quite the 270mm but close enough.

I propose to put a 7x2 timber on top of the supporting wall nearest to me.

Then bridge across to the other beam using joist hangers and either 4x2 or 5x2 timber. The span here is 2.4m, and I would go 400mm centres.

If that 2.4m span is a bit too big for 4x2 or 5x2, I could have another 7x2 joist in the middle (shown in green), which is resting on another brick supporting wall to the left and I would need to attach it to the party wall seen in the picture on the right by means of a ledger board.

danlightbulb · 30 May 2025 at 11:15

@Mysterae_ did you use OSB or chipboard loft boards?

Mercenary Keyboard Warrior · 30 May 2025 at 13:11

You really want a small air gap over the top of the insulation under the boards.
It helps move any moisture than does seep up through the ceilings.
Same as why you want an airgap by the eaves.

Mysterae_ · 30 May 2025 at 14:14

danlightbulb said:
@Mysterae_ did you use OSB or chipboard loft boards?

I used 22mm moisture resistant chipboard flooring from Travis Perkins but I wouldn't recommend that brand.

The price was fine at the going rate but the tongue and groove wasn't the type that angled in and snapped down, more slid in if you know what I mean. Easier to install certainly but it meant that some boards weren't completely flush with their neighbour due to the ceiling/floor not being perfectly flat.

I can't comment on your idea of bridging timbers as that was way more than I did, all I will say is make sure you can get 2.4m lengths through the loft hatch

.

danlightbulb · 30 May 2025 at 14:30

Mercenary Keyboard Warrior said:
You really want a small air gap over the top of the insulation under the boards.
It helps move any moisture than does seep up through the ceilings.
Same as why you want an airgap by the eaves.

Thanks I can understand the theory but in practice it's not possible..it's hard enough trying to get 270mm of clearance for insulation let alone another c.20mm for ventilation gap.

Mysterae_ said:
I used 22mm moisture resistant chipboard flooring from Travis Perkins but I wouldn't recommend that brand.

I've gone for OSB loft boards 3 packs from Wickes £15 per pack. Same price as the chipboard packs and couldn't see it cheaper anywhere else. Would have been slightly cheaper doing it with full sheets of OSB but didn't want to try and manhandle 2.4m lengths of sheet material through the hatch.

I'll be ok getting timber through.

First batch of timber coming monday - 1x 7x2 3.6m joist, 5x 5x2 4.8m joists which I'll cut in half to get my 10x 2.4m lengths. Total £90 from local merchant. That will be enough to get my first section of frame done. Then I can put some of the insulation back into that section and loose lay some boards on top to enable me to start clearing and building the next section along.

Mysterae_ · 30 May 2025 at 14:47

I'd think OSB will be fine, just don't walk on it with bare feet.

danlightbulb · 31 May 2025 at 17:12

Loft light switch currently inside the loft in an awkward spot. Can easily relocate it so...

1. Keep it inside the loft just on the inside of the hatch.

2. Move it to the landing, up near the hatch but either near the ceiling or actually mounted to the ceiling of the landing.

Is it a stupid idea to have the loft light switch in the landing up near the loft hatch?