SISTERING UPGRADED JOISTS

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Northamptonshire
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ATTEMPTING TO CONVERT MY BUNGALOW LOFT INTO A NEW/SPARE SINGLE BEDROOM. I HAVE CALCULATED THE NEW JOIST REQUIRED 50MM X 200MM.
WHAT SORT AND SIZE BOLTS SHOULD I USE TO SISTER THE NEW JOISTS AGAINST THE PRESENT (50X100). IS 500MM SPACING OK ?

SHOULD I USE 50MM X M12 DOUBLE SIDED TIMBER CONNECTORS WITH THE BOLTS?
 
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ha ha,

no hes trying to suggest you dont SHOUT!!

I assume you want to know this for your building regs application?
 
SORRY I WAS ONLY TRYING TO MAKE MY INFO CLEAR FOR EVERBODY. RULES MUST HAVE CHANGED SINCE MY LAST VISIT ! sorry again i just cant help it.
 
ANGLER said:
SORRY I WAS ONLY TRYING TO MAKE MY INFO CLEAR FOR EVERBODY. RULES MUST HAVE CHANGED SINCE MY LAST VISIT ! sorry again i just cant help it.
Shouting does not make anything clear (unless you are in a foreign contry, talking to a local :LOL: )

forum rule 6 has been there for at least the last 2 years which means it was ther before you joined.

I also suggest you read the rules again, since you have also posted in the wrong forum
 
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Can anybody help me with my original request.
__________________________________


+++++++++++++
Your Thread has been moved to "Floors / Stairs / Lofts / Floor Tiling" which we hope will get better response, and tidied a bit.

BTW, 450mm or 400mm intervals will match floor and ceiling materials better

All the best,
Mod Rupert.
+++++++++++++
 
BTW, 450mm or 400mm intervals will match floor and ceiling materials better

All the best,
Mod Rupert.
+++++++++++++[/b][/quote]


didn't i write that some where rupert??

++++++++++++++++++++++
Yes, I think you did, but it seemed to get accidentally lost during the tidying up, so I put it back as best I could remember. Not trying to
claim the credit for your advice!

Rupert.
++++++++++++++++++++++
 
You should not connect new joists to the existing, as when they deflect they will move the existing joists and the ceiling below will crack. The new floor should be independant
 
^woody^ said:
You should not connect new joists to the existing, as when they deflect they will move the existing joists and the ceiling below will crack. The new floor should be independant

so that means that all ground floor ceilinngs are gonna crack then does it woody?? :rolleyes:
 
No, with an existing floor, the floor joists deflect/bend under the initial loading and settle down to a state where only the minor movement caused by normal use and humidity is accomodated by the floor/ceiling as a whole.

When putting a new loft floor in it should always be at least 25mm above the plasterboard ceiling and unconnected to the existing joists, so that when the new timbers do deflect and bend (which they will do) they will not disturb the existing joists and plaster finish.
 
No, I don't do them.

I only design about 5 a month though, and may inspect/manage twice that. Any that arn't done properly get altered and the builder only makes the mistake once.
 
all the joists i have fitted run from wall plate to wall plate as raising them takes too much meat out of the joist (due to the pitch of the roof).

i have never seen a ceiling unmolested due to work carried by building work or by electricians or plumbers. virtually all ceilings are replaced , re- skimmed or under boarded. very cheap and always built into the quote.

it would be foolish to try and maintain the old ceilings whilst this kind of work was going on. no customers of mine would stand for it.

p.s time you did a site visit woody.
 
^woody^ said:
When putting a new loft floor in it should always be at least 25mm above the plasterboard ceiling and unconnected to the existing joists, so that when the new timbers do deflect and bend (which they will do) they will not disturb the existing joists and plaster finish.
That's the way I do it but mostly get away with using 6mm or 12mm plywood on the wallplate so it doesn't touch the plaster lath lumps and you can adjust for joists level etc.
 
I think both methods are valid, i would only ever connect the old with new joists if both were the same size. I would tend towards making the new floor free floating from existing as much as possible to avoid as woody says ceiling settlement. Course this person has posted the question twice and is using less than adequate joists so may need the old ones to make the span work (which i find dubious).
 

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