Service void detail

[jayc89]

I have battens at 600 ctrs infilled with insulation which I plan to lay a VCL across followed by a service void and plasterboard, and have many service void related questions.

 

the void will only be used for electrical wires, so I’m planning on 25mm.
 

The majority of information I have found suggests service void battens should be laid in a single direction (horizontal or vertical), are there pros/cons to one over the other?

Presumably in the opposite direction to the battens beneath the void? If so, should the service void also be at 600 ctrs or different?

 

To allow for attaching the PB should there also be noggins to the service void battens so the PB screwed on all sides?

 

Thanks!

[ProDave]

Fit battens vertically matching the 600 centre stud spacing, that is all you need to do.

 

to make life easy for your sparky, leace a gap in the battens at 450mm above floor and 1150mm above floor in case he wants to run socket and light cables horizontally.

[JohnMo]

I also installed a horizontal batten at the bottom, make attaching skirting boards easy.  Did the same at top of wall also.  But all my wires ran around the house at the top of the wall.

[jayc89]

Thanks @ProDave  @JohnMo no problems with PB not being secured around all edges? I was expecting to to crack where a noggin would normally be screwed into.

[jayc89]

Thinking of a service void for the ceilings now. What's the minimum depth needed to support LED downlights, 75mm?

Edited January 1, 2023 by jayc89

[Kelvin]

You can get shallow downlights. Our ceiling void is made up of 38mm battens and 15mm plasterboard which allows shallow 45mm downlights. 

[jayc89]

Should/could the service void span multiple floors - I'm thinking so new cables could be dropped from the loft space to the ground floor without disturbing the first floor room? I assume doing so would increase the risk of noise travelling between ground and first floor rooms?

[jayc89]

Anyone any suggests on what the junction between a floor void and a service void should look like? I assume having the service void continuous would allow sound to travel. I also assume there are some fire regs to consider, or is the plasterboard across the service void enough? 

[DavidKilburn]

Hi all, just joined this forum - and this is my first post!  Very interested in @jayc89 and what was said re electrical void.  I'm renovating an old farm house - solid stone walls, no cavity. I'm planning on building a box in a box, studding out with 3x2 (not against the wall, but with 10-20mm air gap.  Then going 60mm PIR foil-backed between the studs at 400 centres, and air tight fitted with Gapotape, and then foil taped over the whole lot to create a silver box.  Then was planning on a 38mm vertical stud over the new studs to create an electric / service void.  Thanks @ProDave for the info on a gap at 450 and 1150 for horizonal cable runs.   I'm guessing a 38mm 'secondary' bottom plate where the walls meets the floor would be okay too?

 

But, the question is, will the 12mm PB be okay without horizonal fixings - just vertical ones - any chance of cracking at the joints? 

[jayc89]

2 hours ago, DavidKilburn said:

Hi all, just joined this forum - and this is my first post!  Very interested in @jayc89 and what was said re electrical void.  I'm renovating an old farm house - solid stone walls, no cavity. I'm planning on building a box in a box, studding out with 3x2 (not against the wall, but with 10-20mm air gap.  Then going 60mm PIR foil-backed between the studs at 400 centres, and air tight fitted with Gapotape, and then foil taped over the whole lot to create a silver box.  Then was planning on a 38mm vertical stud over the new studs to create an electric / service void.  Thanks @ProDave for the info on a gap at 450 and 1150 for horizonal cable runs.   I'm guessing a 38mm 'secondary' bottom plate where the walls meets the floor would be okay too?

 

But, the question is, will the 12mm PB be okay without horizonal fixings - just vertical ones - any chance of cracking at the joints? 

I tried just vertical battens in one room and didn’t like the lack of support around the ends of the PB boards so I put uprights at 1200 ctrs in all other rooms I’ve done. Where I’ve run wiring loops, I’ve left the uprights slightly short to allow the cable to pass through. 

[saveasteading]

On 28/12/2022 at 21:34, ProDave said:

to make life easy for your sparky

When we were seeing potential sparks, one asked about wall construction. When we mentioned the services void, his eyes lit up. I think that this showed not only that he would have that facility, but also that we knew what we were doing.  His sensible quote followed and we are all happy.

[saveasteading]

30 minutes ago, jayc89 said:

Then going 60mm PIR foil-backed between the studs at 400 centres

There are previous discussions on BH on the subject of PIR between studs and rafters. I took it all on board (haha). Well worth a read.

It is all true. PIR is hopeless to cut and fit between existing timbers which are at varying centres and inclinations, and still horrible with new timbers..

So 60mm is a good idea, being easier to cut and squeeze in with any accuracy. We ended up using half pir and half mineral wool which fills the whole space, then another pir board as the inner face before void and plasterboard.

.