Hi all,
I'm in a position where a contracter has filled a flat roof but has used inadequate timbers.
The roof has a 5.7m span and he's used 45mm x 220mm at 40cm centres.
Looking at a table from BS 5286-7.2 there is only one timber that will span 5.764m at 40cm cetres and thet's 72 x 220 at a load of less than 0.5N.
Questions...
1. Is it acceptable to bolt on additonal timbers to the existing ones.
2. Also, there are three loads specified in the table, less than 0.5N will allow a weight of up to 51kg/m2.
Its easy to find date on OSB, fibre glass and snow weights, but does anybody what depth of snow to allow for in Leicester?
It could make a big difference if the thickness you need to allow for is greater than say 25cm, it would push you into the greater than 0.5 N & less than 0.75N range.
There's no timber specified at those loads for 5.7m span. I would possibly be looking at having to install steels (very difficult since there ar roof windows).
Any advice?
I'm in a position where a contracter has filled a flat roof but has used inadequate timbers.
The roof has a 5.7m span and he's used 45mm x 220mm at 40cm centres.
Looking at a table from BS 5286-7.2 there is only one timber that will span 5.764m at 40cm cetres and thet's 72 x 220 at a load of less than 0.5N.
Questions...
1. Is it acceptable to bolt on additonal timbers to the existing ones.
2. Also, there are three loads specified in the table, less than 0.5N will allow a weight of up to 51kg/m2.
Its easy to find date on OSB, fibre glass and snow weights, but does anybody what depth of snow to allow for in Leicester?
It could make a big difference if the thickness you need to allow for is greater than say 25cm, it would push you into the greater than 0.5 N & less than 0.75N range.
There's no timber specified at those loads for 5.7m span. I would possibly be looking at having to install steels (very difficult since there ar roof windows).
Any advice?
