Boarding the loft

[Mudball]

Thinking of getting our loft partially or fully boarded .. (mostly partially). This is mostly to get storage space as we are looking to convert part of the garage into kitchen space etc. also Solar survey in a few weeks, they can put all the kit in the loft.

Currently the loft has a bit of a platform to keep for the water cylinder. Otherwise it is insulation on the floor (ceiling of the bedrooms). You can’t step on it as it won’t support weight. The rafters are exposed and there is no insulation on the roof eves.

I have asked a local carpenter to come around and look. What is the best option for loft boarding. Just get something from Wicks? I was told you should not press down on the insulation so need to have some clips to raise the boards. Any advice.

Random Pic from social media of what we are looking to achieve

 

[hairball_89]

If you've got time on your hands, I bought a few boxes of these: https://www.wickes.co.uk/Loftleg-175mm-Loftflooring-Legs-Pack-12/p/100412

with a load of their loft boards and did the job myself. it's time consuming, sweaty (!) work but very easily done if you're remotely handy with a drill, screwdriver and a saw (to get the boarding around pillars etc).

 

[GreiginFife]

Don’t compress the insulation in anyway as it reduces the insular properties.
Get a stilt system of some sort to raise it up.

When I did ours we only had one layer of insulation so I cross battened it with 120 x 45mm battens and cross laid new insulation before boarding over using P5 floor boards.

Possibly overkill but I can walk on it without fear. I don’t think I’d be as confident putting all my 14st on the stilt systems but for just putting boxes up they are fine.

 

[Mudball]

If you've got time on your hands, I bought a few boxes of these: https://www.wickes.co.uk/Loftleg-175mm-Loftflooring-Legs-Pack-12/p/100412

with a load of their loft boards and did the job myself. it's time consuming, sweaty (!) work but very easily done if you're remotely handy with a drill, screwdriver and a saw (to get the boarding around pillars etc).

Can you walk on these… though it is primarily for storage, I need the ability to walk on it.

The other option is to use the reuse the insulation on the roof and use regular flooring to support walking on it

 

[SatchFan]

I just used chipboard loft panels from B&Q. The insulation was already there and flush with the beams so it was just a case of screwing them straight on. Lasted for 15 years until we got the loft converted.

 

[full_throttle]

I just used loft boards, easy to fit
pilot drill holes and countersink the screws and jobs a good one

 

[jim8flog]

Can you walk on these… though it is primarily for storage, I need the ability to walk on it.

according to this their's are OK

Loft Storage Stilts

attic loft storage stilts

www.loftstilts.co.uk

 

[rulefan]

I just used chipboard loft panels from B&Q. The insulation was already there and flush with the beams so it was just a case of screwing them straight on. Lasted for 15 years until we got the loft converted.

You almost certainly haven't got enough insulation depth by current building regs.
The recommended depth of mineral wool insulation is 270mm, but other materials need different depths.

How to insulate a loft or roof: install insulation and save on heating

How to insulate a loft or roof: roof insulation and low heating bills

www.uswitch.com

 

[Mudball]

I was talking to an architect friend and he said it may be easier to get 2inch Celotex to sit on the joists and then put ply/tounge and groove boards on top of the celotex

https://www.travisperkins.co.uk/insulation-board/25mm-x-2400mm-x-1200mm-celotex-pir-insulation-board-tb4000/p/778035

 

[GreiginFife]

I was talking to an architect friend and he said it may be easier to get 2inch Celotex to sit on the joists and then put ply/tounge and groove boards on top of the celotex

https://www.travisperkins.co.uk/insulation-board/25mm-x-2400mm-x-1200mm-celotex-pir-insulation-board-tb4000/p/778035

Having researched insulation A LOT last year when building my workshop, 50mm PIR in a loft space is nowhere near enough. Minimum in a roof space would be 100mm and then it's becoming a very expensive exercise for little to no gain. If it was a bare space being insulated then possibly worthwhile (still expensive) but replacing a whole insulated attic would be nuts, again IMO.

Even in my workshop, which is not a dwelling space I have 75mm in the ceiling as that was the minimum spec to code and therefore the cheapest option as I went 50mm in the walls.

PS. That link is for 25mm (c. 1") Celotex. A sheet of 100mm is around £56 so nearly double the cost. A sheet will give coverage of around 3m2 when accounting for joist spacing.

 

[Mudball]

Having researched insulation A LOT last year when building my workshop, 50mm PIR in a loft space is nowhere near enough. Minimum in a roof space would be 100mm and then it's becoming a very expensive exercise for little to no gain. If it was a bare space being insulated then possibly worthwhile (still expensive) but replacing a whole insulated attic would be nuts, again IMO.

Even in my workshop, which is not a dwelling space I have 75mm in the ceiling as that was the minimum spec to code and therefore the cheapest option as I went 50mm in the walls.

PS. That link is for 25mm (c. 1") Celotex. A sheet of 100mm is around £56 so nearly double the cost. A sheet will give coverage of around 3m2 when accounting for joist spacing.

sorry for the misundrstanding... the loft currently has about 250mm glasswool insulation by the prev owner in 2009. The architect was saying, rather than simply compressing it, add 2 inch of Cellotex board and then put cross ply.
I paid upstairs a visit... i am now wondering if I should bother since it will eat up most of the headroom. But i was thinking all the solar battery and electrics could go on the far wall...

 

[Fade and Die]

sorry for the misundrstanding... the loft currently has about 250mm glasswool insulation by the prev owner in 2009. The architect was saying, rather than simply compressing it, add 2 inch of Cellotex board and then put cross ply.
I paid upstairs a visit... i am now wondering if I should bother since it will eat up most of the headroom. But i was thinking all the solar battery and electrics could go on the far wall...


View attachment 48950

What you gonna do with the corpse? Just cover it?

 

[GreiginFife]

sorry for the misundrstanding... the loft currently has about 250mm glasswool insulation by the prev owner in 2009. The architect was saying, rather than simply compressing it, add 2 inch of Cellotex board and then put cross ply.
I paid upstairs a visit... i am now wondering if I should bother since it will eat up most of the headroom. But i was thinking all the solar battery and electrics could go on the far wall...


View attachment 48950

I’m confused by this. Not sure how the architect thinks you can overlay PIR without compressing the rockwool as all of that is above the joists.
That insulation sets my teeth on edge as it looks like it’s just been thrown in any old way and looks a mess, that’s just my internal OCD overclocking though.

Anything laid on that rockwool especially then heavy boards laid on top will compress it and reduce its thermal efficiency. Whether you will notice that downstairs I don’t know.

If it was me, I’d be looking at finding a few joists and putting a stilt system in for a gangway and raised platform for any solar equipment to sit on, if that’s all it’s for you only need that single platform and access to/from it.

 

[jim8flog]

That insulation sets my teeth on edge as it looks like it’s just been thrown in any old way and looks a mess, that’s just my internal OCD overclocking though.

One thing I know for sure is I would never do DIY loft insulation again. One of the most tiring and uncomfortable jobs I have done in my life.

 

[Mudball]

I’m confused by this. Not sure how the architect thinks you can overlay PIR without compressing the rockwool as all of that is above the joists.
That insulation sets my teeth on edge as it looks like it’s just been thrown in any old way and looks a mess, that’s just my internal OCD overclocking though.

Anything laid on that rockwool especially then heavy boards laid on top will compress it and reduce its thermal efficiency. Whether you will notice that downstairs I don’t know.

If it was me, I’d be looking at finding a few joists and putting a stilt system in for a gangway and raised platform for any solar equipment to sit on, if that’s all it’s for you only need that single platform and access to/from it.

You are right, but putting anything on the rockwool, it will compress it. but the fact you are compressing with another insulation material would mean you are compensating (or is that too simplistic?).

Dont get me started on my OCD. if there was a platform there, i would be rearranging it. BTW, there is a layer of popcorn like Vermiculite underneath the rockwool..

 

[Mudball]

What you gonna do with the corpse? Just cover it?

Now you know where Elvis is hiding.. he never left the building...

 

[GreiginFife]

One thing I know for sure is I would never do DIY loft insulation again. One of the most tiring and uncomfortable jobs I have done in my life.

Totally, that’s why I tried to ensure it was done properly so I don.t have to revisit it.

I even went to the extent of creating access hatches in the flooring to access down lights and speakers if needed.

 

[GreiginFife]

You are right, but putting anything on the rockwool, it will compress it. but the fact you are compressing with another insulation material would mean you are compensating (or is that too simplistic?).

Dont get me started on my OCD. if there was a platform there, i would be rearranging it. BTW, there is a layer of popcorn like Vermiculite underneath the rockwool..

I think it’s too simplistic as the PIR isnt going to be airtight if it’s just laid on top of rockwool. When installing PIR it’s installed tight to joists and then sealed with expanding foam.

If it’s like polystyrene beads it could be EPS that’s been put in, total rubbish from all of my research, the consensus was avoid at all costs.

From a cost perspective a small, simple stilt system would be far cheaper and more efficient than laying about £400 of 50mm PIR across all that.

 

[Mudball]

I think it’s too simplistic as the PIR isnt going to be airtight if it’s just laid on top of rockwool. When installing PIR it’s installed tight to joists and then sealed with expanding foam.

If it’s like polystyrene beads it could be EPS that’s been put in, total rubbish from all of my research, the consensus was avoid at all costs.

From a cost perspective a small, simple stilt system would be far cheaper and more efficient than laying about £400 of 50mm PIR across all that.

Tnx.. I have a mortal fear of walking on stilts . So would be more secure if the carpenter puts some cross batten and then put ply on it ..

 

[GreiginFife]

Tnx.. I have a mortal fear of walking on stilts . So would be more secure if the carpenter puts some cross batten and then put ply on it ..

That’s what I did. 120 x 45 (nominally 6 x 2s) perpendicular to the main joists, then 150mm rockwool laid in between these new joists and then P5 floor boards over the top.

The new battens are secured using countersunk 180mm coach screws every 600mm. As above, where there is a down light or speaker that might need accessed, I cut a small hatch and hinged them using cut down piano hinges and cut the insulation in a square that I can pull out and replace if needed.