Help with steel/floor levels in loft conversion.

[Watshot]

I have various steels to fit into my loft conversion, some of which run parallel with the joists, trimming stairs etc. My problem is that the joists are generally 147mm deep and the steels in question (which were specified at 152mm deep) vary from 151mm to 158mm. The point being that they will sit higher than the joists thereby lifting the floor.

Is it normal to floor around them and infill the top of the steel with a slip of thinner timber and then lay your finished flooring, carpet whatever, or would you route out part of the t&g sheets to accommodate the higher steel?

Or have I missed something at the design stage? When the calcs say 6" joists and 6" steels I thought they would be the same, but obviously not.

I could drop all of the ceilings to accommodate the difference but I'm sure this must be a common problem. Just wondered what the normal solution is. Much obliged for any advice!

 

[Static]

Do you have any headroom issues? If not then you could use 175mm deep joists for the flooring (but you will lose 17mm on floor-ceiling height)..

 

[Watshot]

The joists are all in and the steels sat in the garage waiting to go in, so unfortunately back tracking now is not really an option. I have been fighting to maintain as much headroom as possible as well.

It seems to be a material issue, whilst the joists and steels should have the same depth it appears that there is some 'manufacturing tolerance' built in which I had not considered until too late.

Couple of similar posts seem to have gone down the route of planeing the difference off of the floor boards where they sit on the steels. This would appear to be the easiest option, I was just looking for reassurance that this was acceptable really.

 

[freddiemercurystwin]

There are no manufacturing tolerances with the steels, steel beam sizes vary depending on their weight per metre.

Untitled

• freddiemercurystwin
• 21 Jun 2010
• 1

So for a 152x152x23, 23 is the weight of the beam per metre and it is 152.4mm deep X 152.2mm wide.

 

[Watshot]

Thanks Freddy, that explains the differences with the steels, makes more sense now. Seem to recall reading that the timber at 152mm was 'regularised' or something which made it all 147mm. And therein lies the problem, a difference of about 11mm in depth between the timber and the '30' weight steels.

That's the trouble with DIYing a large project that I'm unlikely to repeat, lots to learn, no use for it afterwards!

Anyway, unless anyone has a reason why not, I think I shall plane/route out a channel in the floor sheets to accommodate the higher steel. Many thanks.