New house - loft conversion

[HammieUK]

Evening!

As of today I'm a proud home owner, and I'd like to get your opinions on a loft conversion in my new place that one of the previous owners did. I was almost certain that the loft had not been built with building regulations approval, since it wasn't advertised as a bedroom, and today I found a letter under the attic carpet that actually said 'this bedroom was built without building regulations approval'

Anyhow, I'd like to get an idea of how much work would be needed to bring it up to scratch, save me any nasty shocks when I get a builder round to assess it. I popped up some of the floor boards to look at the reinforcements, it appears to have a steel joist at either side of the room ('L' shaped, approximately 4" x 4" x 1/3"), then 2" box section is run between these to support the floor. I wasn't able to see how it was anchored to the walls unforuntately, and as far as I can tell there's no RSJ through the centre, the room's roughly 10' x 14'. My biggest concern is whether the reinforcements are good enough, since this is the biggest bit of the conversion, any idea?

I also had a look at the stairs, I believe there's a minimum headroom requirement (though the number escapes me), I'm certain these stairs aren't sufficient, as I knock me head on one of the steel joists on the way up. I think the staircase would have to be rebuilt, about 1 foot fowards, I think the reason this wasn't done in the first place is that it would obscure the corner of a window slightly (I'd rather have a safe staircase than a square window though )

As for things like insulation and fire proofing, I have no idea, I don't expect those to meet regulations but they're 'minor' fixes. Thanks in advance for any advice, I hope to be doing a lot of DIY this year so I'm sure it won't be the last time

 

[HammieUK]

Here's a couple of pics to give you an idea what I'm blabbing on about...

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• HammieUK
• 30 Apr 2010
• 1

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• HammieUK
• 30 Apr 2010
• 1

 

[freddiemercurystwin]

Edit: just re-read your post.

Phone Building Control and get them out, they'll visit without being appointed so don't worry about them charging you. they'll tell you exactly what they'll be looking at to get your approval sorted out. They'll look at, amongst other things, adequate structure, insulation, a compliant staircase, fire regs for the rest of the house, you'll need fire doors on every door ground and first floor that opens onto the stair landings and mains smoke alarms ground and first. Its pretty hard to give advice on the structure unless you provide some more info.

 

[HammieUK]

Sounds good, I'll see if I can arrange a visit from building control in the next few weeks. Silly question, they're not going to condemn my house or something rediculous if there's things not up to scratch right?

In the meantime, any more ideas if the floor might be sufficient (obviously no one could say for certain on this forum, I'm expecting either a 'maybe...' or 'not in a million years')? I'm not sure what else I can give you in the way of details, what would you need?

 

[freddiemercurystwin]

Size of house ie distances between walls, position of and size and number of any steel beams, are the RSJs box sections, angles etc. What are the spans. What are the spans, sizes and centres of any timber floor joists. Draw a crude drawing of what's where if its easier than describing it.

For example:

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• freddiemercurystwin
• 30 Apr 2010
• 1

It doesn't have to be as elaborate but you get the idea, only if you can give us this information can we give you a good idea if you're existing structure will need beefing up or not.

 

[freddiemercurystwin]

Silly question, they're not going to condemn my house or something rediculous if there's things not up to scratch right?

No although they may record it in their file as being non-compliant works.

 

[big-all]

my personal guess is it would likley be cheaper if they hadnt done anything
and most off what they have done will need to be ripped out

 

[HammieUK]

Numbers are a bit rough without measuring but hopefully should give an idea...

- The house is detached, 14 foot between gables, 18 foot wide.
- There are two steel beams in the attic , running from one gable to the other, these are separated by 12 foot. These are 4" x 4" angle section, 1/3" thickness.
- There are approx 10 steel beams running between the larger steel beams, 2" box section, can't tell the thickness, length 12 foot, welded in place.
- The floor space extends between the gables, and between the large steel beams (i.e. there's no floor space that's not supported in some way by the steel)
- There are no timber joists supporting the attic floor, but there may be some hidden supporting the ceiling below.

Hopefully that's enough info, i'll do a sketch if it's not clear enough.

 

[freddiemercurystwin]

Oh bigall!

Harsh...............










but true, I was trying to break him in gently!

 

[freddiemercurystwin]

- The house is detached, 14 foot between gables, 16 foot wide.
- There are two steel beams in the attic , running from one gable to the other, these are separated by 12 foot. These are 4" x 4" angle section, 1/3" thickness.

These, in a typical lofty would normally be RSJ's around 180mm in height. spanning between them would be timber joists around 175 in depth. Your loft floor, apart from being very unconventional, sounds hopelessly under-engineered. Building control will, if they don't tell you to rip the lot out and start again, demand calculations from an engineer to prove they work. These will very likely prove the structure is under-engineered. Big-all has very likely hit the nail on the head.

 

[HammieUK]

Ha, don't worry, I fully expected that really! I'm really just planning on what order I'm going to things in my house, if the reinforcments were sufficient I would have planned on bringing it up to scratch first, if not I would make it my very last priority due to the significant work required adding new RSJs. So is it a lost cause?

 

[freddiemercurystwin]

By your description it sounds as though it is. This is what properly sized steels look like: http://www.aboutloftconversions.co.uk/sg2-steels.html

 

[HammieUK]

- The house is detached, 14 foot between gables, 16 foot wide.
- There are two steel beams in the attic , running from one gable to the other, these are separated by 12 foot. These are 4" x 4" angle section, 1/3" thickness.

These, in a typical lofty would normally be RSJ's around 180mm in height. spanning between them would be timber joists around 175 in depth. Your loft floor, apart from being very unconventional, sounds hopelessly under-engineered. Building control will, if they don't tell you to rip the lot out and start again, demand calculations from an engineer to prove they work. These will very likely prove the structure is under-engineered. Big-all has very likely hit the nail on the head.

Thought as much, 4" angle section did seem pretty pathetic, even an 4" I section (which I would expect to be several times stronger) sounds undersized. Maybe in a few years I'll think about redoing it all, till then I'll keep dreaming . Out of interest, you said it's unconventional, are you talking about the use of angle section, the box section or something else?

 

[freddiemercurystwin]

Unconventional as in having angles (instead of RSJs) and having steel box sections (instead of timber joists).

 

[HammieUK]

Ok, next question - does it look like the roof is correctly supported? There are 4 purlins supporting the rafters, these are approx 4" x 10". There may be a few vertical timbers transferring some load from the rafters to the original wooden joists, but they're sparse if they are there. Most of the loft conversion guides I've seen have started with trusses supporting the roof, which seems to differ from this design, was it always an open space or has the former bodger just hacked out the central timbers?

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• HammieUK
• 1 May 2010
• 1

Apologies for the funny angle, you can see the 4 purlins from outside the house in the pic...

Also, could any recommend me a good book on loft conversions? The internet is somewhat limited on info. Thanks again