Boarding Garage Walls

[Bobbya82]

Hi

I want to plasterbaord out my integral garage walls (Brick outer/block work internal) and just had a couple of questions regarding insulations and membranes.

I know walls can be dot and dabbed with insulated plasterboard but it seems battening them could be a better way, does the below sound ok/correct.

Batten the walls with https://www.buildbase.co.uk/homegrown-cls-50-x-100mm-x-10m-10386-2825810 400mm apart

Fill with https://www.wickes.co.uk/Kingspan-TP10-Insulation-Board---2400-x-1200-x-25mm/p/180435 Not sure if 50mm would be better

Then board with foil backed plasterboard like https://www.travisperkins.co.uk/Kna...lasterboard-2400mm-x-1200mm-x-12-5mm/p/858201

One other question was do I need to put a breathable membrane or a vapour control layer onto the blockwork before I put the battens on, not sure exactly what the differences are? such as
https://www.roofingsuperstore.co.uk...MI5Jez7p7w4wIViK3tCh3u7wTgEAQYASABEgIDRPD_BwE
or a Vapour control layer? https://www.jjroofingsupplies.co.uk/klober-permo-light-vapour-permeable-roofing-underlay/?infinity=ict2~net~gaw~ar~331981876075~kw~~mt~~cmp~Breathable Membranes | Klober | Underlays (6)~ag~7424 - Klober Permo Light Vapour Permeable Roofing Underlay&gclid=EAIaIQobChMIisu7y6Dw4wIVQ7DtCh2MsQRLEAQYASABEgIiFfD_BwE

Also I plan to put joists on the floor, which membrane would I need to put down on the concrete floor before putting the joists down?

Many thanks for your help.

 

[Notch7]

Is it a cavity construction?

You could fix 50mm celetex tight to the walls, continious. Fill gaps with foam and foil tape all joints.

Then screw on 50 x 25 battens laid flat.

Then plasterboard - foil backed if you really want belt n braces.

The advantage of doing this is that the insulation is continuous so no thermal bridging at studs and the studs are not fixed to a cold poss damp wall.

The foil on the insulation board and joined with foil tape does the job of the VCL.

Disadvantages of doing this way: no option for packing out studs if wall really out of plumb. On single skin walls, there is the risk of moisture getting through brick to back of insulation -although Im not sure thats an issue really, tge vcl will stop warm air getting to the wall so no issue with condensation.

 

[Bobbya82]

Thanks for the quick response, yes cavity wall.

I think some of the the walls might be out in some parts.

You read so much about different ways I am trying to get a simple plan that I can just stick to.

If not going for suggested method do I need breather membrane and a VCL also what would I need on the concrete floor before putting down joists?

Thanks again

 

[^woody^]

If it's a cavity wall then you dont need a VCL or foil boards.

You may be better off with 50x25 treated roofing battens and 50mm of insulation - either 25mm between and across the battens, or get 50mm and notch it to cover the front of the battens. Battens should be at 400mm centres not 400mm apart!

You need a DPM across the slab, and to fill any voids in the new floor completly with insulation

For the joists, if the slab is not level you will be messing about with the joists, so consider putting the joists on hangers - with insulation below to avoid a cold bridge, and insulation between.

 

[Bobbya82]

Thanks woody that’s great, it is a cavity wall but I am not sure the cavity is actually filled! Does that make a difference so no VCL or foil boards needed?


So, do you mean 50x25 battens straight on the bare block wall and then 25mm insultation between and then 25mm over the top of the battens and the other 25mm, is the insulation glued or fixed to the wall and battens and then screw the plasterboard over the top?


Yes centres.


Would something like this be ok for the slab DPM https://fulhamtimber.co.uk/product/...MIxvTk58bw4wIVSLTtCh3nNgoGEAQYAiABEgJ6_vD_BwE


Apologies for all the questions


Appreciate your help.

 

[^woody^]

VCL's are for timber frames, not masonry walls.

50x25 battens straight on the bare block wall and then 25mm insultation between and then 25mm over the top of the battens

Yes.

Wedge the insulation between, then a couple of token screws for the insulation across the face before its held with the plasterboard screws

Yes that membrane is the one but its way too much. Have a look at Toolstation.

 

[Bobbya82]

Thanks again, really helpful to get things confirmed so I am not making mistakes.

sorry one last question, the ceiling is boarded and their is a bedroom above, rather than taking down existing ceiling and replacing/inspecting insulation can i just fix insulated plasterboard like this? Does it have to be insulated?

Many thanks

 

[^woody^]

You dont need to insulate a floor between habitable and heated rooms.

Whether it's worth doing whilst all the other work is going on, or whether the limited insulation values of thermal board and loss of head room is worth it, is up to you.

 

[Bobbya82]

Brilliant thankyou.

If I did decide to have 50mm battens and 50mm insulation could I just use foil backed plasterboard or normal plasterboard, do the battens need covering with insulation.

Really appreciate all your help.

 

[^woody^]

You can use either plasterboard. Not covering battens with insualtion can lead to stains running up the wall where ever the battens are in contact with the plasterboard, and is bad pratcice.

 

[Bobbya82]

Thanks good to know

Which fixings and screws would be best to attach battens to blockwork and insulation to the battens?

I take it you don’t batten round the window or insulate? Assume you can just stick the plasterboard on as there only small parts?

Also is it best to board the ceilings or walls first or the floor?

Many Thanks

 

[^woody^]

Use min 75mm m6 or m8 hammerfix or similar for the battens. Black phosphate plasterboard screws for the boards.

You should insulate around the window head and reveals, but no need to batten. 10mm insulation will be enough, you should be able to saw down the centre of a 25mm insulation board.

Do the walls last, it don't matter if you do the ceiling or floor first.

Don't forget that the DPM should run up the external walls at least past the DPC, or about 300mm.

 

[Bobbya82]

Cheers Woody, that’s made things a lot clearer.

 

[Bobbya82]

Thanks for all your help with this, i was just wondering if instead of using 25m of insulation in between the battens then 25mm on top then the plaster board, would it be ok instead to put the 25mm inbetween the battens and then just put combined plasterboard and 25mm insulation such as https://www.planetinsulation.co.uk/ZPL4025.php ?

Many thanks

 

[^woody^]

You could do.