New build timber framed problem

[jstephens251]

Hi everyone,

Thought I'd post here to see if any of you have wired new builds single storey, no loft with foil back insulation.

Its a high spec new build - downlights, data cables, speakers wires etc

I have attached a pic of the ceiling which has just been finished.

The problems i've got is there is barely a 40mm gap so drilling through will put me way out of regs. This stuff is stapled tight to ceiling so bit of a nightmare really.

Wondered what others have done to comply with regs.

Cheers, Jon

 

[Toneyz]

I think the consensus is counter batten the ceilings Don't know what the walls are like but could not some of the RFC etc. cable runs go in horizontal to the sockets

 

[LankyWill]

I bet if you ripped the battens off and pulled that quilt insulation back it would reveal some joists. How else has wet pants plumbed it? Probably a case of impatient builder not waiting for you to first fix. Tell him to get the mongo labour in with a hammer to rip that insulation back.

 

[Toneyz]

Wet pants could be putting in floor however I was thinking along the same lines but the photo wasn't conclusive

 

[Leesparkykent]

I done a house similar to this last year. The company who supplied the timber frame was Scandia-Hus and the insulation looks the same. The builder reckoned the insulation was nearer the £200 mark a roll. The insulation was stapled to the rafters and studs. The studs were cross battened and the ceilings were dropped just enough to get down lights in using MF. The house wasn't far off passive house status.

 

[LankyWill]

That insulation is always made redundant anyway, as soon as you nail it on you create thermal bridging reducing the insualting properties by minimum 40%

 

[ValewoodElectric]

Architects give me headaches. They design everything with the smallest of tolerances because it if meets code it meets code. Sure it can be built and maintained but if they used their head a little bit and designed with more room in mind, installation would go much faster and be cheaper in the long run. As Ian said at the top of the page, maintenance rewiring on this is going to be a nightmare.

 

[stummish]

I love architects. They're so deluded. The rewire I'm doing at the moment has no measurements or consideration for routing pipes/cables.

I once had a fire alarm call point marked in the middle of a doorway! It even showed which way the door handed, I was so tempted to drop a 20mm steel in the middle of the hallway and send the pic to the architect for his critique!

Back on topic, batten off the ceiling, collingwood halers h2 fit in a 60mm void. Notch and joist plate cable routes, plasterer will hate you but that's pretty standard anyway. When they call you for any modifications in years to come tell them they'll have to have surface trunking, that'll be a laugh!

 

[jstephens251]

I bet if you ripped the battens off and pulled that quilt insulation back it would reveal some joists. How else has wet pants plumbed it? Probably a case of impatient builder not waiting for you to first fix. Tell him to get the mongo labour in with a hammer to rip that insulation back.

Hi, plumber is ok its UFH. All piping is going in concrete floor so he's sorted.
Theres no builder really its a timber frame company who have built and insulated the shell. Insulation is stapled really tight so I would basically make it a right mess pulling it apart.
Customer is enquiring on battening ceiling out which hopefully happens.

cheers for help guys, much appreciated.

 

[Toneyz]

This company does a lot of kit type construction for the self build market a gang comes along and erects the frame in a couple of days then goes off site they would not come and go around trades it would not surprise me if there is a joist above insulation.

 

[cliffed]

Like the guys say,only way is to cross batten

 

[Midwest]

I once did a new build a quite a few years back,the architects name was Ian Goodenough
It is a genuine name for a guy that actually was good enough

As a bit of light hearted relief, I worked with a guy called Richard Cockhead, apparently it's pronounced 'Cohead', and for some reason, he insisted on being called Richard.

Also knew a cop called Police Constable Crook.

 

[Wilko]

Those of us who remember Maxwell Smart - I have met his namesake who was in the non comedic branch of that endeavour. I told him to get a real alias as that one was taken. He was not amused

 

[Lee42]

Hi.

If there is no chance of cross battening I would notch the joist and put plates across them.

There is slim downlights that would fit and give great light output. I'll post an image off them.
The ones I have fitted in the past are aura enlite

I think keff do some slim speakers too

 

[jstephens251]

Hi.

If there is no chance of cross battening I would notch the joist and put plates across them.

There is slim downlights that would fit and give great light output. I'll post an image off them.
The ones I have fitted in the past are aura enlite

I think keff do some slim speakers too

View attachment 36423

Cheers.

So, in case this battening idea didn't pan out is notching the joist and putting plates on acceptable with regs?

 

[stummish]

I've never done it but I thought that's what joist plates were for. Someone else will have to confirm that.

 

[Lee42]

As long as a screw can't penetrate the plate I can't see a problem with it

 

[stummish]

@Lee42 the plate gives some nice mechanical protection, so you can bury at less than 50mm, but the other reason is the steel shores up the weak spot in the joist. Support strength comes from the top and bottom surface of a joist, the center doesn't do much to hold the rest up, so the steel replaces the lost strength is how I understand it.

Like I said though, never used them and my ideas are based on the wet toilet paper between my ears, not fancy evidence or proof.

 

[Lee42]

You will not need them to support the notch as looking at the picture they are not structurl joists. They look like 2 x 1 that have been nailed on over the top of the insulation so when plasterboarding they have something to screw to.
My main concern would be whoever is plasterboarding accidently screws through a cable. Which is why I would put plates over the notches.

Hope that helps

 

[davesparks]

If they won't batten the ceiling down then they can't have recessed lights or speakers, it's pretty simple really

 

[Lee42]

If they won't batten the ceiling down then they can't have recessed lights or speakers, it's pretty simple really

I agree on the speakers but there is recessed lights on the market that will fit in there.
The light in the picture i posted is only 25mm deep so once u add the depth of the plasterboard u will have enough room

 

[Toneyz]

I agree on the speakers but there is recessed lights on the market that will fit in there.
The light in the picture i posted is only 25mm deep so once u add the depth of the plasterboard u will have enough room

This light fitting is all well and good but the driver needs to go somewhere and not in contact/surrounded by insulation.

 

[ThomasW]

Hi everyone,

Thought I'd post here to see if any of you have wired new builds single storey, no loft with foil back insulation.

Its a high spec new build - downlights, data cables, speakers wires etc

I have attached a pic of the ceiling which has just been finished.

The problems i've got is there is barely a 40mm gap so drilling through will put me way out of regs. This stuff is stapled tight to ceiling so bit of a nightmare really.

Wondered what others have done to comply with regs.

Cheers, Jon

View attachment 36413

Before drilling any pre-fabricated roofing joists I'd talk to the manufacturer first because this might seriously weaken the structure. In my opinion there is always an opportunity to install cables at the lowest apex where no-one should be in a position to damage them and without drilling the structure.