A kind of loft conversion

[NBee]

Hi. I live in the 1st floor of a maisonette, of which I have the leasehold. The property has a lovely big loft which I want to partially convert.

I don't want any windows or internal partitions, which I know would require architectural approval. All I want to do is to carry out structural alteration to the roof trusses so that the loft is free from obstruction, and then to insulate and deck the floor, and insulate and panel the inside of the roof area.

As there will be no changes to the exterior of the property, and very little changes to the internal loadings, what kind of approval would I need to do this work?

Do I need permission from the freeholder?
Do I need an architect?
Do I need building regs approval?

Any advice on this would be very much appreciated!

 

[masona]

All depend what you want to use the room for.It not quite straight forward as you think,the ceiling normally consist of 4"x2" joist which will bow with extra weight.You will have to put in a bigger joists and then you can altered the roof truss which connect to the new bigger joists as it will give extra support to the roof.You can only use 2" insulation on the roof rafter so the air flow behind it go to the top of the newly roof vent to let the timber breathe.Are you having staircase ? Like I say,depend what you want the room for.Best get down to local planning for advice,normally drawing + building reg.

 

[NBee]

Thanks for the response!

I have no plans to build a staircase, I shall use the existing loft hatch. I will be using the loft as a kind of extra space - I may stick a lightweight pool table up there. Like I say there will be no more weight in it than it has had before, and the floor will be evenly decked out to spread the load. I would certainly not classify it as an extra room.

Does this make any difference?

 

[masona]

Okay,depending on your joists span,if it feel solid (not springing) you might get away with it and after a period of time the ceiling could start to show hairline crack.If it a longer span then you could put something like 6"x2" joist along the side of the existing joists with nuts/bolts together and rest it on the bearing support walls which will take the extra weight and feel more solid.

 

[robmorphet]

what about building regs? could they fine you for an non-approved conversion?

 

[masona]

Providing NBee doesn't altered the structural alteration to the roof trusses,if so it become building regulation + drawing.There a lot of people out there boarding their loft out as play/room area and using loft ladder providing they haven't altered the structure of the roofing section,then it okay.It doesn't count as a extra room when selling it on.

 

[NBee]

Ah, but I would have to get alterations to the roof structure. I want to open it up so that it has no obstructions.

 

[robmorphet]

thats what I'm trying to achieve.

I've got PP but need Bregs Perm too. Cant find a builder who'll do it so thought balls, I'll do it myself. Then I found out about the fines for no BRegs approval etc.

My thought was to suppport the trussed roof with 5*2 timbers running from wall plate to ridge and wall plate to wall plate, so creating a number of triangles side by side to the existing trussed structure. Once these have taken the roof weight, and I've bolted the exisiting ceiling joists to the new floor joists, then I'd remove the trusses, leaving the org. frame and a much stronger supporting one, and loads of room for a new bathroom and bedroom.

That then removes the need for massive steels to be inseted in an other wise very awkward site.


does anyone know that:
If:
the existing roof sits on the wall plates,
Why cant I do the above? There's very little difference in weight and the load is thus spread over a far great area, reducing stress over a solution where we insert steels to support the truss removal.

I think your at the same level I'm at NBee, Bloody frustrated and wanting to get on!

 

[masona]

Your idea is good but the roof rafters will bend in the middle even with 5"x2"and eventfully the weight will push the rafter where the birdmouth is off the wallplate even it is nuts & bolted. (birdmouth is the cut out on the rafter where it join onto the wallplate) then your roof will crash down! The roof section need upright support from minimum 1/3 of the lenght from the wallplate,this is where you could start your steel joists then wallplate on top of it,upright support & purlin across it with cross member supporting the purlin.You don't really need a builder but a good carpenter to advise you.Personally I would get building permisson and then you can still do it yourself.If you're near Southend area I can help you.

 

[robmorphet]

i live in the NWest!
typical!

cheers for the tips - gonna keep thinking about this as there must be away for the DIYer to do this!

Maybe I need Tommy Walsh!!
have a nice bank hol. all..

 

[robmorphet]

just thought,

I wouldn't need to cut a bird mouth in the rafter as its connected to the new floor/ceiling joist, creating a triangle. ie 3 bits of timber per support. Each join would be bolted together and so they would self support?

 

[masona]

Try and use a bigger joist like 8"x2" than 5"x2" if you can on the floor level which should take the weight of the roof,then 1/3 up from the bottom put in your upright support wall with nuts/bolts & timber connector.(timber connector will stop the timber slipping apart).See this www.fastfixdirect.co.uk/prodimages/0697T.jpg

 

[robmorphet]

thats superb, thanks for the advice masona

rob

 

[masona]

Forgot to mention you will need square plate washer on both side of the bolt head & nut side as well,otherwise the bolt will pull into the timber.Keep tighten it until you cannot see the timber connector !

 

[Cheesy]

Is it vital that a square plate washer be used rather than a similarly-sized round washer?
We build some fairly large wooden structures for theatre, which is my only previous experience, but no-one there has ever mentioned making joints the way one would to comply with building regs. If I was copying what we've done for some of the large scenery, I'd be using hex bolts (so you're not relying on the wood to hold the bolt head), large-ish round washers and a second nut as a locknut, but no timber connector. This doesn't sound like it would comply with building regs but is commonplace in theatre.