loft convertion

[garybain37]

I’ve been drafted in to help my mate to convert his loft into a computer room, he is not doing it to Regs its but we will be doing the best job possible.
He’s got a builder friend in to give us some direction so we have a good idea of what’s required.
My question is will 50mm Jablite polystyrene insulation be sufficient to put between the roof joists before we plasterboard over the top ? The joists are 75mm so we will have a 25mm gap for air flow.
Also the builder told us to remove the loft insulation before we put the floor down (we will be putting in additional beams to compensate for the extra load) is the removal necessary or can the insulation stay ?

 

[masona]

I’ve been drafted in to help my mate to convert his loft into a computer room, he is not doing it to Regs its but we will be doing the best job possible.

I'm afraid the builder is wrong!

Normally you only need to follow building regulations which is straight forward, best to give the BCO a ring.

Failing this, it will have to converted back to how it was or when the property is up for sale and the insurance policy is worthless.

Think about the safety issue, if there is a fire below how are they going to get out?

 

[jbonding]

why are you asking for the right way to do it but not involving bco, it doesn't make sense, it costs pennies but will save you pounds. give your head a shake

 

[markie]

The insulation can stay it will damping the sound so when someone walking around in loft you will not here them as much from below

Just a few
how are you going to put in the extra floor joists ?

how big are the joists ?

The insulation for the rafters should be 90mm ( if done by regs) your useing 50m

If you sell the house the loft can stay as it is but you can't count it as habitable room such as a bedroom, sitting room, all it can be noted as, is storage area

 

[garybain37]

Thanks Markie for a productive answer, my friend knows he won’t be able to sell as an extra room he just wants to move his computer up there to free up a bedroom for his kids.
The joists are 5 x 2 and there are 2 of them running the length of the loft, we intend to put 3 more in at 6 x 2 and will hang them on heavy duty joist hangers bolted to the wall, we will bring the original joists up to the same size.
I doubt the old insulation on ceiling will have much effect as it’s barely 2’, I was just worried about cold spots & condensation.
We intend to have the outer storage area un-insulated with just the floor extending out & then insulate the inner box (computer room). We are using 18mm chipboard flooring & 12.5 mm foil backed plasterboard

 

[gaz2923]

when you sell your house if you dont have building regs you can simply use a lack of building regs indemnity policy via your solicitor which is relatively cheap at around 20 pounds for a house up to 100k in value

bear in mind though that there is currently no limitation of time for which the bco can find out about your conversion and make you make it compliant or put it back to normal following the case of cottingham attey bower (i think thats the case)

 

[masona]

Thanks Markie for a productive answer,

So masona & jbonding has given you bad advice

 

[garybain37]

Your advice was not bad Masona it was just not what I’d hoped for, we’ve taken on the fire issue & he’s having an emergency escape window fitted & alarms connected to the mains (which he was doing anyway)

Didn’t mean to offend

 

[BOB NUTS]

Gary

"he is not doing it to Regs its but we will be doing the best job possible"

that sentance is somewhat of a contradiction . The Regs are the very minimum safety standards - the best job possible would be way in excess of these standards.

I take it that your not going down the legal regs route for a reason. Normally that would be because you dont want to meet the minimum standard for some reason.

I think the main question has to be - which of the regs in particular are you trying to dodge?

(by determining which regs are the problems it will be easier to tell you what you want to know )

In response to your initial questions

- 50mm Jablite will be woefully inadequate

- So will 25mm air gap - is there suitable high and low level vents to feed the gap?

- the 75mm rafters? are you sure these are traditional rafters as that sort of size timber is often associated with roof trusses

- did the builder tell you to renew the insulation or just remove it - if the latter it doesnt sound (lol) like hes giving a particularly informed opinion (what other advice has he given )

 

[jbonding]

Your advice was not bad Masona it was just not what I’d hoped for, we’ve taken on the fire issue & he’s having an emergency escape window fitted & alarms connected to the mains (which he was doing anyway)

Didn’t mean to offend

ooh so it must of been me






































only joking gary, what i meant was it sounded like you were gonna do most of the stuff proper why not go the full hog for a couple of quid more and a lot less heartache in the future

 

[masona]

The joists are 5 x 2 and there are 2 of them running the length of the loft, we intend to put 3 more in at 6 x 2 and will hang them on heavy duty joist hangers bolted to the wall, we will bring the original joists up to the same size.

Do you mean add another joist on top of exsisting joists? If so, not the correct way, should be coming off the wallplates on the side of the ex-joists with at least 8" high A bit difficult without seeing it, any photo?

 

[garybain37]

On our houses the wallplates don’t come up high enough to rest the joists on. The joists in our houses run the full length of the house so we will bolt the additional joists to the party walls on either side, the joists will fall on walls within the house able to take the load.
I’ve now found a document relating to sound deadening & insulation which seams to give all the info needed (going to insulate the ceiling now)
As for the Regs issue………. My mate is one of those people that cant stand still, gets an idea and it needs to be done (yesterday!!!!) so it’s a time thing + he’s not got the recommended head room where the ladder is & if we moved the access point it would take us into a bedroom.
I’ll take some piccy’s & try to download them (anything to give you boys a laugh ), will measure the rafters again
Thanks for your input so far
how do you attach a file or photo ??

 

[masona]

how do you attach a file or photo ??

See here

 

[garybain37]

Hopefully I’ve uploaded some photos with this post!!!

My terminology might have been off in my previous posts , what I’ve been calling JOISTS have been the long 5 x 2 running the length of the loft 2 in number & we intend to add 3 more at 6 x 2 & put our floor on them
What I’ve been calling RAFTERS is the triangular frame work which holds the roof up which is 4 x 2 on the slope & 3 x 2 for the ceiling
Hope I’ve got this right

 

[garybain37]

woohoo i've done something right