sagging joists

[guest627]

Hi

we have sagging joists. Probably by 1 inch in the middle of the room. How can we strengthen them?

These joists in the loft. They seem to be pretty standard and around 4m long if it matters. We want to use loft as a storage room, but it seems to be too risky.

Could you reccomend anything, or where to read about it?

Many thanks

 

[k2kris]

In all fairness you are better to contact a Structural Engineer of sorts if they are deflecting that much with no load & you are thinking of using it for further storage. If they have defelcted that much I would imagine your ceilings have cracked as well?

One of the eaisest methods is to 'double up' your joists & then bolt them together. But I would take further advice before moving forward.

 

[masona]

Any photo?

 

[guest627]

Many thanks for the answer,

I am afraid I have exaggerated (not intentionally, I just double checked this morning) The sag is less than 1/2 inch probably, maybe even less than 0.7 sm, and not all joists, only couple of them are sagging that much. The others are also moving though, if I either step on them or try to put some pressure from underneath.
Apparently, there was nothing"wrong" with the ceiling. There are chipboards (or something very similar) nailed to joists with some gaps between them and all this was covered with plastic (or whatever they are made from) tiles. We removed these tiles and discovered that joists were flexible. I think since these tiles were flexible, noone has noticed anything before., and nothing was cracking (there are gaps between these boards).

So pictures would not help probably (and I do not have digital camera...), sorry.

Given that the sag is smaller, do you think that the idea to double these joists is still the best?

 

[masona]

Do you have ceiling binders which is a bit like a joists (4"x2") in opposite direction of the ceiling joists?

 

[guest627]

Many thanks

we do not have these binders. We only have these joists which are parallel to the shortest wall, (and apparently also parallell to the only one other supporting wall in the middle of the house!). There is also one other piece of wood (looks like joist) that goes in the opposite direction, in the middle of the loft, but it looks like it lies on joists, and is not connected to any walls. It seems that the only purpose of this "joist" is to hold some electricity wiring.

 

[masona]

Sagging joists will never goes back to the correct position, your best bet is to run something like 5"x2" joists along the side of the exsisting joists and resting on the bearing wall or wallplate.

 

[guest627]

Thanks,

the next step is to understand how to get these new joists into the loft, without breaking anything... Oh...

 

[k2kris]

Try remnoving 1 - 2 tiles on the roof allowing joists to be slid in rather than knocking off all your best china through the house! This is normally the way when doing loft conversions i.e. through the velux window opening