Redoing a loft conversion

[HammieUK]

Evening,

Last year I bought my first house, a nice detached 1930's place with a few problems due to the previous over ambitious DIYer, the biggest of which is the loft which isn't to building regulations, and basically needs ripping out and starting again (confirmed in another thread I started last year). I've attached a few pictures detailing the current construction, they're not to scale however. It's a strange arrangement of angle steel bolted onto the ceiling beams, with steel box section welded onto that, this would never pass building regulations so needs completely redoing. The existing room is fairly cosy at 4.5 x 3.1 x 2.0, but I think it would make a nice guest room (or cinema room )

It should be a relatively straightforward conversion, since I'm not modifying the roof structure, and there's no party walls, however there's insufficient headroom for the staircase at the moment (only 1.67m), I can easily bang my head on the binder above the stairs, and I can't move the stairs forward as it would cut across a window on the 1st floor landing. I think the basic order or work would go something like this:

- Remove existing steels and staircase
- Fit 2 x RSJs parallel to the binders
- Tie ceiling joists to RSJs to take the load, then remove the binders
- Fit floor joists into the RSJ webbings
- Fit staircase
- Sort gable window (this worryingly looks like it's been built without a proper lintel!!)
- Fit roof windows
- Fit insulation and fireproofing
- Rebuild stud walls around landing
- Electrics, decorating etc

By removing the binders, I think I can get the required headroom for the staircase, has anyone seen this done before? Obviously I'll be getting proper calcs and plans made up, I'd just like an idea of whether this would work.

Also, does anyone have an idea on cost for doing the structural stuff (fitting RSJ, tieing to ceiling joists, fitting floor joists and removing binder)? I plan on doing most of the other stuff myself (except for the staircase and gable window), so it would be the main cost in this conversion.

Thanks

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• HammieUK
• 7 Jan 2011
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• HammieUK
• 7 Jan 2011
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• HammieUK
• 7 Jan 2011
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• HammieUK
• 7 Jan 2011
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• HammieUK
• 7 Jan 2011
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[Deluks]

Bit late for that lot, but 1 question springs to mine. If the previous roof supports have been removed, what's holding the roof up? Purlins usually need support from struts or stud wall in the eaves.

 

[HammieUK]

The lower purlins may be supported by struts, but I need to remove some of the plasterboard to find out (will do that this weekend). The upper purlins appear to have no supports (other than the gable walls), it's possible they were previously supported by the partition wall that runs most of the way down the house, I'll investigate that this weekend too.

If there was additional supports there before, what could be done to remedy it? Obviously adding struts into the middle of the room wouldn't be suitable, can the purlins or rafters be reinforced?

 

[masona]

Do you know what's supporting the ceiling binder underneath?

Don't want to worry you as you may want to get legal advice regarding the loft room done incorrectly as you may have paid the wrong price for the extra room and your solictor should've spotted it regarding no building permisson plans, you will need to spend quite a bit of money to put this right and the last owner may have to reimburse the cost to you and this is where you may need legal advice as I'm not an expert in this field

Also, does anyone have an idea on cost for doing the structural stuff (fitting RSJ, tieing to ceiling joists, fitting floor joists and removing binder)?

All depends what the drawing plans passed on, on my conversion, had to pay for the stress load calculation on my footing but failed therefore ended up putting in bigger joists, if you're going ahead then get the drawing made up who will advise you at the time as this maybe the best way to go what could be done before drawing plans submitted

 

[HammieUK]

Actually I was completely aware it wasn't to building regulations, it was advertised as a 'study room' but had clearly been used as a bedroom, although it's not even legal as a study room. I was able to get a significant discount on the house because of the conversion, it went on the market at 175k, a number of people tried buying it but had their mortgage rejected because of the conversion, I didn't have that problem though because I have a private loan, ended up buying the place for 116k. Based on other house prices on the street, I should be able to increase its value by a minimum of 20k, so it should be a sound investment.

As for the structure, I don't think there's anything below supporting the binder, it's just supported by the gable walls. They're a reasonable size, about 6" x 3", with a 4.5m span.

When you say you had stress load calculations done, I presume you mean you calculated whether the existing joists were suitable? Fitting steels and larger joists are a certainty, it's very rare for ceiling joists to be beefy enough. I'll be getting quotes for plans this weekend, found a few local architects who specialise in loft conversions, hopefully they can recommend some local builders for the job too.

 

[freddiemercurystwin]

You do not need an Architect, technician will be fine and probably much less too.

 

[Static]

You will also need to justify the structural alterations that have been done, so chances are the Architectural Tech will get a Structural Engineer in to give a report on whats been done and what needs to be done to fix things..

 

[masona]

When you say you had stress load calculations done, I presume you mean you calculated whether the existing joists were suitable?

The stress load calculations is for the RSJ whether the footing can take the weight of the RSJ of the 4 pressure points in the bearing wall, I only have the slab type footing hence why I have to have bigger joists to spread the load instead of RSJ

 

[HammieUK]

Well I've started removing some of the plasterboard and floorboard, and what I've seen so far is a bit scary. My main concern so far is the state of the walls around the purlins on one side of the house, it looks like they're crumbling away beneath them!! It also looks like it may have been hastily repaired at one point, but I'm no builder, anyone any idea what's happening?

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• HammieUK
• 14 Jan 2011
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• HammieUK
• 14 Jan 2011
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I'm also quite confused about what's going on with these struts, as they don't appear to actually be doing anything...

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• HammieUK
• 14 Jan 2011
• 1

There's 4 struts along the purlin length, and each one is supported by a small bit of wood which is sat ontop of a couple of ceiling joists. I can't imagine these are contributing to the roofs strength in the slightest, I'm thinking they've been installed by the previous owner as some poorly thought out supports. Any idea what on earth they're for?

 

[masona]

My main concern so far is the state of the walls around the purlins on one side of the house, it looks like they're crumbling away beneath them!!

Judging by the photo, that's pretty normal to me

I'm also quite confused about what's going on with these struts, as they don't appear to actually be doing anything...

I think you just got to forget what's happening, best to get the drawing done for the RSJ's or bigger joists then strengten the roof as most of the work is done for you