Raised Attic flooring - low roof

KungPao

Hi,

I am looking to install some attic flooring, just an area for storage. I am using 18mm OSB bonded to 100mm EPS on top of joists, with 100mm mineral wool insulation between. I reckon this is the way to go to maintain sufficient insulation and satisfy current regs. Around the flooring will have 300mm mineral wool insulation in and over joists.

I have read I should do the same as a walkway to the tank, which is at other end of attic, however the roof is low, as in you can't stand up as it is so low, never mind with losing another 120mm or so. This is fine for the storage area, but if a plumber had to work at the tank he'd effing and blinding with such a lack of space. And I would too cleaning the tank etc.

Anyway, for this walkway would it be alright to just have OSB directly on joists, with 100mm insulation underneath? I could roll over some mineral wool and roll back when walkway is needed. Or would I expect to get guff re regulations if I want to sell the house at some time?

Or am I overthinking it all?

Calahonda52

is the tank plastic?
are you insulating the tank?
are u insulating under the tank and all exposed pipes?
Why would you need to be cleaning it.
IMO keep the insulation the same on the walkway all the way down.
Else you could put some eps or similar between the joists, perhaps?, under the walkway

listermint

Forget the wool go with a good grade PIR between the joists . With nice UValue

KungPao

Calahonda52 wrote: »

is the tank plastic?
are you insulating the tank?
are u insulating under the tank and all exposed pipes?
Why would you need to be cleaning it.
IMO keep the insulation the same on the walkway all the way down.
Else you could put some eps or similar between the joists, perhaps?, under the walkway

Tank is plastic, will do a nice insulation job on it, not insulating underneath, and for some reason the tank is lidless, so god knows what lurking in there - need to give it good cleaning before sticking a lid on it and insulating it, and no harm giving it the occasional clean too imo.

Yeah for the walkway to tank I think I’ll just put eps or pir between joists and board over. Cheers.

Calahonda52

The correct way to do the tank is insulate it underneath, we have moved past the old way.
The lid needs a vent, mouse proof.
Really no need to be cleaning the tank unless you have a lot of dirt in the incoming.
The sediment just settles in the bottom, below the outflow

John mac

Calahonda52 wrote: »

The correct way to do the tank is insulate it underneath, we have moved past the old way.

how do you stop the water from freezing ?

Calahonda52

John mac wrote: »

how do you stop the water from freezing ?

Insulated all the way around, even an uninsulated cover makes a huge difference, and the tank will never freeze solid in Ireland

youtheman

Calahonda52 wrote: »

Insulated all the way around, even an uninsulated cover makes a huge difference, and the tank will never freeze solid in Ireland

Can happen on a very rare occasion. My Mother lives about 1 km from the coast in Kerry. Went to collect her for Christmas in 2010. Walked into the house and couldn't understand why the radiators in some rooms were not working. So went into the attic and found the complete tank frozen solid. So just shut off the mains and left. dropped her back a week later. when I turned on the mains she said there was water dripping down the ceiling. so shut tha mains again before any damage done. so I got a kit from the local electrical wholesaler consisting of a uv lamp and frost thermostat (just for that 20 year event). I'm old enough to remember the 'big freeze' of 1982, 1990 and 2010 !

KungPao

I think I'll insulate the heck out of the tank - PIR board "sarcophagus" and covered in mineral wool for good measure, but leave the underneath bare. The way I see it, it's best to have some warmth going into the tank so my electric shower isn't working overtime to heat the water, and the CH too isn't working too hard to heat the water.