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Double joist joining

Posted: Sat Dec 05, 2009 4:26 pm
by slawekj
Hi as beginner DIY I'm looking for advice how to best join 2-No 150x47mm joists to create double joist.
1. What is better - nails or bolts?
2. What size/type of bolts/ nails use?
3. How to space/ locate nails/ bolts for good connection?

I will be very thankful for any help.

Posted: Sat Dec 05, 2009 9:00 pm
by gwb
use M8 110mm coach bolts,measure down 30mm from the top and bottom of the joists and drill through both the timbers and bolt together space the bolts out 600mm all the way along from one end to the other,should be strong enough for a tap dancing elephant.

Re: Double joist joining

Posted: Sun Dec 06, 2009 9:44 am
by ollyburton
slawekj wrote:Hi as beginner DIY I'm looking for advice how to best join 2-No 150x47mm joists to create double joist.
1. What is better - nails or bolts?
2. What size/type of bolts/ nails use?
3. How to space/ locate nails/ bolts for good connection?

I will be very thankful for any help.

hello there 1st of all if the timber is bowed put this upover,bolt every 200mm with coach bolts m10 that shold hold anything
________
fake weed

Posted: Wed Jan 06, 2010 11:30 am
by jackthebuilder
Hi

Would suggest M12 bolts rather than M8 or M10 - worth the extra cost, and use timber connectors (Screwfix 99094) between the timbers.

You might think that these will create a small gap between the timbers, but the holding power of the spikes on the timber connectors is far greater than the friction between timbers butted together - no matter how hard you tighten the bolts!

And use a 12mm drill and hammer in (if necessary) the bolts- don't use a 12.5 or 13 because it's easier to get the bolts in!

Hope that helps.

Jack.