strengthen loft

[danped]

I have a loft which I thought I would like strengthened. The reason for
this is over the main bedroom there are a couple of cracks in the
plaster where the ceiling has been flexed a little. The ceiling is
perfectly flat though (i.e. no sag)

What I want to use the loft for is storage. But I'd just like to have the reassurance that it is sturdy and won't come crashing down.

So I got a (loft specialist) builder round for a quote and another is
coming later in the week. He suggested a method of strengthening which
was good, but I sort of got the impression he wasn't totally convinced
it was necessary. So I'd like some opinions.

I've posted a picture of my loft here:


In total the length is 22 foot, it is 12'6" from the front wall to the
inside load bearing wall and 9'6" from there to the back wall. The
purlins running from the front are 9" x 3" and those at the back are
slightly thinner at 7.5" x 3". the purlins are 10'6" apart.

The beams making the ceiling / floor which run perpendicular to the
purlins are 1.5" x 3" at 16" gaps but for each span there are two
pieces of this each about 15" long which overlap in the middle and are
nailed together. (These bits can't be seen in the photo for the
insulation.) Running across the top of these is three pieces of 2 x 3
which I think simply braces them.

Then coming down are some thin pieces of wood from the roof which
support the ceiling at the apex of the roof and at the purlins.

My question is how suitable is it for boarding out at present and is
there some easy way to make it stronger such as adding some additional
ceiling hangars from the purlins to the beams? I'd appreciate any other
advice or suggested reading.

Thanks.

 

[noseall]

there is probably nothing you can do with this type of roof to stiffen the ceiling joists without undoing, and potentially harming what you've already got.

the ceiling binders and purlins look a shade tired and slightly inadequate by todays standards but thats only a minor criticism.

i personally don't agree with the vertical strapping as this only helps the ceiling deflect when the roof deflects. i would rather see sturdier roof members installed in the first place and do away with the vertical straps.

if it was a clear floor space you were looking for and to rid yourself of the ceiling binders altogether, then you are treading on dangerous ground.

if it was making the existing ceiling stiffer, then installing new sturdier thicker section ceiling binders is equally an awkward job.

 

[danped]

Thanks for the reply. I've got a few more questions...

i personally don't agree with the vertical strapping as this only helps the ceiling deflect when the roof deflects. i would rather see sturdier roof members installed in the first place and do away with the vertical straps.

I thought the vertical straps were holding the ceiling up, not holding the roof up?

if it was a clear floor space you were looking for and to rid yourself of the ceiling binders altogether, then you are treading on dangerous ground.

Thats ok, I am not after clear floorspace, just storage space

if it was making the existing ceiling stiffer, then installing new sturdier thicker section ceiling binders is equally an awkward job.

Are the ceiling binders the vertical straps? One of my thoughts was to use some 90 degree twist ties to support the joists from the purlin, then I thought I could glue and screw some more 3x1.5 on top of the current ones across their full length to stiffen them and prevent flexing.

 

[noseall]

yes the vertical straps are there to help stiffen the ceiling, but the roof will deflect slightly with wind and snow loads, this is transferred to the ceiling via the vertical strapping.

if the roof and ceiling were built of adequate timber sections, therefore doing away with the vertical strapping altogether, then the roof and ceiling could deflect independently.

this is just my opinion though. no doubt ^woody^ will tell you different.