meccarroll":1w0etlfn said:
TrimTheKing":1w0etlfn said:
Yes mate a few pages back I think. There is a diagonal of brickwork between the two roof sections that needs supporting and the structural engineer has also specced steel ridge beams so I don't need any rafter braces.
Cheers
Mark
Which braces are not needed Mark, Diagonals under the rafters, longitudinal, collar near the ridge?
I can see the need for support under the return brickwork/block work on the internal return but I do not know how a steel ridge beam replaces the bracing.
My learning has been that bracing in the roof counteracts any wind forces acting on the gable (pushing against or puling effect caused by a vacuum of passing wind). The effect the bracing in a roof acts similar to bracing in a ledge and braced door.......... it stops any forces pushing or pulling it out of shape. If wind forces, push against your gable how does the steel ridge at the top stop the wind from pushing the roof and gable over?
I'd just like to obtain an understanding of the engineers theory regarding how the steel ridge counters the forces on the gable :eusa-think:
Any clues Mark.
Cheers Mark
Hi Mark
Short answer, I haven't clue! I will run it by him but I've spoken with Mike G and unless I misinterpreted his take on it my understanding is that with the steel ridge beam I no longer need any kind of horizontal bracing across the rafters at any height, the reasons why though I didn't venture into.
Perhaps if Mike reads this he can add some insight otherwise I will ask the structural engineer to clarify to make sure I haven't misunderstood his intentions, but I was very clear in my remit which was to have steelwork built that would enable me to not have any horizontal ties between rafters if at all possible.
Just reading your comments again though, I fail to see how collar ties or any kind of horizontal bracing would protect from what you describe! Surely collar ties or eaves height joists are surely just there to stop the weight of the roof from spreading the walls apart…!? None of that would help or prevent the wind effects on the gable… :eusa-think:
Cheers
Mark