Sagging Floor Ciling / Joists *Excessive Notching* Pics

kodak

Hi,

Looking for some advice or opinions here!

There are two rooms affected in a 1960's house.

The top floor is spilt into a flat and so is the bottom. We are currently renovation the downstairs and there is Gas heating just about to be installed upstairs.

The Rooms are 3 meters wide and the Joists are 6" x 2 1/4" ( 150mm x 50 mm)

Somebody have notched and drilled holes excessively in the first room and there is small areas of dead wood worm in the second.

There is quiet a lot of bounce in the joists when walked on from upstairs. You can also feel the bow in the wood when walking upstairs.

I know the ideal and best solution is to remove all the joists and re do the both rooms but would extra bridging help reduce the movement as i'm afraid the plaster will crack when we will put it up.
Redoing is the least attractive option as upstairs is pretty newly renovated and people living in etc.


Any thoughts appreciated.

mp22

How about doubling up on the joists?

wayoutwest

Hi Kodak.The problem you have is that the joists are not deep enough to stop any bowing/bouncing.Putting in lots of very tight and well screwed noggins may take a little out of the bounce.MP22-if you were to double up the joists as suggested,how are they fixed?-set into the wall and then screwed to existing joists or just screwed?.Either way would require taking down wiring first.You could put in a "summer"beam(6x5ish timber]from underneath and set it into the walls -this will create a solid floor and during the process of fitting you could take the worst of the bow with two accro props.You can use a nice bit of timber and make a feature of it, or plasterboard over some rough stuff.If using this method look out for the following points 1.You might not want to reduce headroom 2.Cental position of beam might co-incide with lintel or chimney breast 3.Centrally placed ceiling light not possible so consider spotlights etc.

sky6

Your problem is that there weren't enough noggins put in in the first place. The Best solution as wayoutwest has suggested is to jack up the ceiling on Accro props to take the Bow out of the Ceiling. I would then put in two 6 x 5 Beams and make a feature out of them. You could then plaster the underside of the ceiling between the beams. This will give the room back it's feeling of head height and it should look really well. Best of luck with it.

mp22

If the joists were doubled up setting them into the wall and bolting them together is the only way to go,stripping out some cables might sound like a lot of work,but would be worth it in the long run.

wayoutwest

Mp22-setting the new joists into the wall might be a lot of awkward work depending on the material that has to be chiselled out (mass concrete , soft brick etc.).They dont want to be sitting just on the thickness of the plaster. Bolting the new joists to the old ones sounds a good idea - what size of bolts and what spacings would you use?

mp22

10 mm at 1m centers and those large star washers between the timbers.

kodak

Hi,

Thanks for all the suggestions.

There is only two cables going to a double socket upstairs in each room at the minute.

The walls are made out of mass concrete on some walls and blocks.

I think i'll jack it up and put as many nogins as reasonable practicle in and then review the situation and put 1 or 2 summer beams in as suggested.

Where would I get a summer beam and does anyone know approx cost?

jack of all

The joists are way undersized to begin with, 175x 50mm would be the minimum for a span of 3m. The notching is excessive and holes are not bored on the centrelines. Best and most reliable solution (as already suggested) is to jack up the floor/ ceiling and break the span with a steel universal beam, set into pockets in the walls on cast concrete padstones. The beam will need to be lined in plasterboard for fire resistance. Timber bridging alone will be of negligible benefit and arguably only adds additional weight to a floor which is already struggling. Once the floor span is shortened you should turn your attention to the excessive notching, by partnering with new timber or plywood scarfing, bolted or glued and screwed to the existing timbers. I'd also brush on a bit of protim to prevent any new infestations. Steel beam is only an option if you can get a length into the room of course (any you'll need 3 or 4 men to get it into position, depending on the weight). Now would also be a good time to introduce a bit of quilt insulation between the joists for (limited) sound deadening. Two layers of plasterboard (joints staggered) would improve sound performance and fire resistance significantly.

hamish262001

Bridge it.

Had a bouncy floor in a house i brought last year 7" joists spanning 3.5 meters with minimal bridging and a lot older than 1960's

floor is grand now

lash on the protim then fit 2 or 3 rows of bridging make sure they are tight and near to full height 6"

PaulieBoy

You could also look at using angle irons. Sit them in the joist along the span.