Fixing flat roof joists ?

Sudsonic

I am in the process of putting a new flat roof on my shed / workshop. my plan is to bolt 4" x 1" timber onto the top of the block walls and then lay the joists on top at each side but I'm still not sure of the best way to fix the joists to the top of the walls ?

Any suggestions !!!

sydthebeat

nail joists to wallplate.

strap every 4th joist down to block wall with twist straps that incorporate fixings for wall plate as well.

include solid bridging at eaves location.

gsxr1

as syd said. Buy yourself a bag of 3 or 4 inch nails depending on your joist size. You will get a better fixing if you double up your wall plate.

Nail the the first wall plate to the wall using masonry nails then nail another one on top with 3" wire nails. This mean you will have a good depth for using stronger 4" nails to nail the joists down. Buy wall plate straps and a box of washer nails to fix them to the masonry.

also. make sure you wall plate is pressure treated timber.

Mellor

An alternitive to joist straps are wall playe straps, and an alternitive to this is bolting the wallplate to the wall at small centres

ircoha

IMO, while it is a bit more time consuming, I would bolt the wallplate which should be 4" by 2" pressure treated onto the wall at say 800mm centres.

Unless u are well used to working with them, masonry nails are not the easiest to work with.
If u do make sure you wear good eye protection.

Drive the nails at an angle from the side of the rafters into the wallplate, use a pilot drill hole to make it easier

Wall straps are fine if u are plastering the inner walls else they look...

jack of all

My choices:

Traditional
Bolt down a 4"x3" (100x 75mm) wall plate to top of wall with bolts at 1200mm c/cs. Underside of plate to be brush treated with preservative. Skew nail each joist in position (one nail; each side of joist), 4" wire nails.


Modern solution:
Fix wall plate in position with express nails (temporarily holds plate in p[osition only), fix joists in position (skewnailing) and use twisted straps to tie the lot down.

gsxr1

ircoha wrote: »

Unless u are well used to working with them, masonry nails are not the easiest to work with.
If u do make sure you wear good eye protection.

k...

good point . I lost two finger nails as an apprentice nailling wall straps.

I use pliars to hold them now till the nail gets a good start.

Sudsonic

Thanks for the replys.

Had thought of skew nailing them in place but thought there may have been a more substantial way of doing it. Will use some straps as suggested also, right wheres my hammer

RKQ

There are galvanised brackets / shoes available, to fix joists to wallplates. They are used mainly in timber frame construction and look like small joist hangers.

I remember a roof that was blown off a building and into a carpark in a very violent storm. It resulted in a court case where both the builder and architect were held responsible, as the wallplate was bolted down. Part of a row of blocks went with the roof.

Less likely to happen on a small shed but would still prefer 600 or 900mm long straps at 1200mm centres. Both lengths cost about €2 each.