Loft conversion advice....

[sythai]

Evening Chaps....

Just seeing if anyone out there has done/does the electrics for many loft conversions. Only done the odd one many many years ago when first started out on the books.

After a fair bit of perseverance have managed to get myself in with a local company that specialise in that area. First job in September, hopefully lots more to follow :smiley2:

Any pointers/ anything different to maybe be aware of from a more conventional type extension ?

I'm presuming there will normally be some sort of enabling works where first floor lighting cables / TV may be running over the top of existing joists may have to be relocated, along with any fan ducting ?

One thing which I have noticed is there seems to be a lot of smokes specified - x 12 ! Currently a 3 bed semi, changing to 4 bed with the conversion. Might have to see if I can get some sort of AICO deal at the wholesalers:yesnod:

Any thoughts would be greatly appreciated,

Have a good weekend,

Sy

 

[Dave 85]

12 smokes? You're having a giraffe right? In a 4 bed semi?

 

[Guest123]

Supplying new circuits to the loft from the CU (if required) is probably the biggest headache, along with re-routing existing cables etc.

Finding the CU is too small, lack of bonding/RCD, the usual stuff etc.

Interlinking smokes, if a real problem can be overcome with radiolink bases.

A good stock of MF J/B's would be a good thing IMO.

 

[Des 56]

I'm presuming there will normally be some sort of enabling works where first floor lighting cables / TV may be running over the top of existing joists

Not really,they usually have to fit a suspended floor​

 

[sythai]

12 smokes? You're having a giraffe right? In a 4 bed semi?

Think the architect got carried away... oh well I'm not complaining, has made up almost half of my estimate .

​

 

[topquark]

The smokes throughout will be an additional requirement as you're now adding a third tier. As will new fire doors on all other floors (so make sure they're not changing the hanging from left->right vice versa; as that'll move the switch positions).

Biggest headache is that the insulation (usually celotex rather than the multilayer stuff) if often put into the ceiling space before the internal walls are up, so getting first fix right is a "challenge/opportunity". If I do another I'd consider running the cables in the floor space and take up the walls (for the smokes/switches/isolators) as (due to some last minute changes) I had to move one of the switch wires (which was a pain)...haven't really thought that through fully, just an observation. What goes into the ceiling insulation wise is 90mm between rafters + 20mm over the whole surface, then the plasterboard (leaving 50mm above the celotex for cables etc to run and drop through to accessories).

It's also a good idea to spec a non maintained emergency light at the top of the stairwell (as you don't get a lot of either natural or street lighting on that floor).

You'll also want to consider the existing light switching for the other floors (incorporating a new intermediate) so you're able to control all floors landing lights from all levels.

Wirelessly connected smokes all the way for this too.

Also installed satellite cable to each room along with two ethernet points (one high level for TV and one at desk height).

 

[sythai]

The smokes throughout will be an additional requirement as you're now adding a third tier. As will new fire doors on all other floors (so make sure they're not changing the hanging from left->right vice versa; as that'll move the switch positions).

Biggest headache is that the insulation (usually celotex rather than the multilayer stuff) if often put into the ceiling space before the internal walls are up, so getting first fix right is a "challenge/opportunity". If I do another I'd consider running the cables in the floor space and take up the walls (for the smokes/switches/isolators) as (due to some last minute changes) I had to move one of the switch wires (which was a pain)...haven't really thought that through fully, just an observation. What goes into the ceiling insulation wise is 90mm between rafters + 20mm over the whole surface, then the plasterboard (leaving 50mm above the celotex for cables etc to run and drop through to accessories).

It's also a good idea to spec a non maintained emergency light at the top of the stairwell (as you don't get a lot of either natural or street lighting on that floor).

You'll also want to consider the existing light switching for the other floors (incorporating a new intermediate) so you're able to control all floors landing lights from all levels.

Wirelessly connected smokes all the way for this too.

Also installed satellite cable to each room along with two ethernet points (one high level for TV and one at desk height).

Thats great thanks for that some good info there... cheers Sy

 

[sythai]

The smokes throughout will be an additional requirement as you're now adding a third tier.

They've got another one coming up where it becomes 4 storeys and the requirement is a sprinkler system !

​

 

[topquark]

They've got another one coming up where it becomes 4 storeys and the requirement is a sprinkler system !

​

PMSL, I think a word with LABC might be in order for that one if it's definately domestic. They may let that one go.

PS Also ask about the requirement for low energy lighting (they may not be too pedantic on that front either).

 

[Lucas]

We tend to run a 10mm from the board up to the loft space and mount a little sub board up there. Normally run a ring, lighting circuit and smoke circuit. They are normally pretty straight forward as all run out of studwork.

 

[topquark]

Looked at the part B doc. The sprinkler is an alternative to providing a second escape route if building is over 7.5M apparently.

 

[Silly Sausage]

After I nearly burnt my house down, I fitted a smoke alarm in every room, hallway & landing apart from the kitchen & bathroom. Should have fitted a heat alarm in the kitchen, but too late now.

You have to leave the house when the lass sets them off 'cooking'.

 

[Taylortwocities]

Looked at the part B doc. The sprinkler is an alternative to providing a second escape route if building is over 7.5M apparently.

I've often wondered about that.
Normal sprinker heads operate at around 70°C. I think I would rather have an escape route rather than having to wait around in 70°C and hoping that the sprinkler is going to start!

 

[topquark]

Yep, that's what we did with the loft extension, smokes in every bedroom (3 beds with two ensuites) and the landing; kids rooms and likely to be full of electrical kit.

 

[Silly Sausage]

I think the smoke will have killed you first, before sprinklers go off.