Upgrading loft bracing.

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Hi all,
When I bought my house a year ago there was an advisory regarding loft bracing. When I enquired about this he said there was a lack of diagonal bracing to the roof trusses. Also a lack of ties on the gable wall. Looking closer there are metal ties on the gable wall but no noggins between the roof trusses.

I have done a bet of research and I have the typical Fink roof truss. I plan to install the diagonal and horizontal bracing with extra metal ties to the gable wall. I was thinking of 100 x 25mm treated sawn timber screwed to every truss.

Firstly does this sound like a good idea?

Secondly, what wood do I need, is standard treated sawn timber ok? (I don't want wood worm or rot later). Do I need to tie in the gable wall the other end, which is a dividing wall between the two semi-detached houses?

Apprciate any advise.
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Can anyone advise?
Many thanks

 

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I'm guessing C16 sawn treated would be ok. What do you guys think?

 

[Static]

To be honest without knowing everything about your roof its really hard to comment.. but as a minimum 25x100 overlapped over two trusses at joins is standard (unless you are in a non standard area for wind/snow loading or have a non standard roof configuration)..

 

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To be honest without knowing everything about your roof its really hard to comment.. but as a minimum 25x100 overlapped over two trusses at joins is standard (unless you are in a non standard area for wind/snow loading or have a non standard roof configuration)..

Thank you very much. That is basically what the surveyor said regarding the size of the timber. I am from the essex area and don't believe to be in a non standard area.
I wondered if normal sawn timber was ok for the job or if a more structural timber was required. I am not sure what they normally use.

Thanks for your help.

 

[catlad]

100x25 rough sawn treated timber get the longest that you can get through your loft hatch, attach them with 65mm galv wire nails diagonally from ridge to the wall plate put 3 nails in each truss.

 

[ladylola]

I'd change catlads advice slightly and advise screws rather than nails, there's less chance of accidently dislodging a tile due to all that hammering.

 

[JohnD]

I don't know, but it might help to add some photos of the roof timbers, with dimensions (thickness, depth and length)

 

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Thanks for the help guys. I was thinking screws too due to the hammering. I will take a few pictures now and post up with sizes to give a better idea.

 

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Ok just been up there and measured the joists holding the ceiling up and the joists that the tile battens nail on to (sorry not sure what they are called) These measure 35 x 95mm. the rest of the supports that make up the whole roof truss are 35 x 70mm.

The roof trusses go the whole length of the house which is approx 7.4m. There are stud walls below.
It was hard to take some good pictures, but hope the one below gives you an idea. It is looking at the gable wall end of the house.

View media item 42396 View media item 42397
Many thanks for the help.
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Just to add about half way across the span under the ceiling joists is a stud wall, I guess this could be load bearing to help with the span.

While I am at it I am going to board some of the loft for storage. I'm just a bit worried about the amout of weight. Any ideas what sort or weight a loft can take?

Don't want to cause any problems.

Many thanks

 

[catlad]

If there is a supporting wall in the centre then I would say you can board it in the centre say a metre either side.

 

[JohnD]

I am not a roofer, but those trusses look OK to me. The Truss manufacturers have compurt programs to calculate how to make them for any size you input, so they are just strong enough, with the minimum material.

I wonder if the surveyor might have had in mind bracing across the row of trusses, to prevent them falling over like dominoes? Once the house is built, with gables and tile battens, they are most unlike to do that. Can you see any bracing that runs from top front to bottom back, nailed to all the trusses?

Trusses are designed to be strong enough to hold up tiles with snow on it, the plasterboard ceilings, and an occasional builder walking about up there, nothing heavy. Water tanks are usually on doubled trusses, and positioned above a supporting wall. If you want to floor it, I'd always recommend counterbatterns laid at right angles to the trusses, to spread the load of your weight over several trusses, and 18mm ply (not chipboard). When all this is screwed tightly together, it will give quite a rigid deck. You can lay insulation between the counterbattens, so make them 75mm at least deep. You can store christmas decorations, but nothing heavy like boxes or magazines, and you shouldn't have more than two people up there, and they should not be standing next to each other.

 

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Thanks for your help.
The report says both cross bracing and diagonal bracing.

I have got one diagonal brace on the opposite side to where the pictures are taken. But it is not nailed to every truss only about one in three!

The water tank is not on doubled trusses but is close to the gable wall on cross batterns at right angles to the truss.

I was only thinking of storing my xmas decorations, suitcases and a box of about 15 old books up there, the books may be a bit heavy then! may have to find a different place for those.

The wall in the middle is only a stud wall and so I guess would not be supporting anything.

 

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Do you guys think that it would be a good idea to treat the current timbers that are in the loft with a preservative while I am at it?

I hear horror stories of woodworm and rot, and always think prevention is better than cure!
Any recomendations to the preservative?

Thanks
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