# Forum Home Renovation Pergolas, Gazebos, Strombellas & Rotundas  Roof bounce - movement

## Paulb007

Hi, Ive just bought a house that has a pergola/carport attached to the side of the house. 
Its 7mx3.6m and has trimdek as roofing. The posts are 90x90 rhs3.0mm and the headers ect are all c Chanel 100x50. Now it seems to have a bit (2/3 cm) of up down movement in the center.  I have drawn a crude plan of how its built... now my question is what can i do to stop the movement... more rafters? some cross bracing??

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## Paulb007

no ideas??

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## phild01

How many posts?
Where are the posts located?
Is that 2/3 of a cm or 2-3cm, presume 2-3.
What is it that makes it deflect that much, just it's own weight?

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## Paulb007

3 posts + one attachment to house. so house then 1.7m to post,then 1.7m then post, then 1.7 then post then 1.7m edge. does that make sense? no sorry its 2 to 3 cm of deflection when there is a large amount of wind, i can grab it and pull it down and make it move also. under no stress (me or wind) its nice and square/ level.

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## Paulb007

post location

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## Uncle Bob

I'd say only extra posts or bracing would help. Is there a chance you're unnecessarily worrying too much about this? Usually these types of things have been engineered for wind load.
It's not like you'll be lifting engines out of cars from this roof. Or will you?  :Wink:

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## Paulb007

No, no engines coming out with this one....car is under it and thats where she will be rebuilt though.  

> I'd say only extra posts or bracing would help. Is there a chance you're unnecessarily worrying too much about this? Usually these types of things have been engineered for wind load.
> It's not like you'll be lifting engines out of cars from this roof. Or will you?

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## phild01

pictures help get better responses.  If the flex is in the unsupported corner then of course an extra post will help.  If only in the centre, then a reinforcing beam between the centre post and house would take care of that.

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## METRIX

> no ideas??

  Give people time to respond, this is not an instant live response forum.

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## cyclic

Thickness of the 100x50 may have a lot to do with it. 
Also how the frame is joined. 
Give us a pic of the centre area where the frames join assuming the bounce is in the middle and not outside of the posts..

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## Bloss

But what is the problem? If the carport has been there for some time as it seems to have been, and has not yet deformed, collapsed or blown away, then movement/ flex in the steel sheet roofing of 2-3cm on a roof that is 7m long and only in high winds is not a big deal. Pictures might help, but it is probably well within its design specs so should just be left alone. 
If you did want to do somethings then additional beams sistered to the existing ones then additional roof fixings or simply applying some tension to the existing beams to transfer the loads at the centre to the outside i.e.: the posts using some steel rods and turnbuckles for adjustment or by creating web trusses by adding some gal reo inside the beam channels 
But as I opened with - I don't think there is problem to be fixed.

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## Paulb007

its not a very old carport, think it was done just before it went on the market. Joins are std c channel connectors. pictures are attached. its only that center where there is movement. nothing on the edges or the header.

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## Bloss

Looking at that looks very normal and would have been constructed to the engineered and approved specs. Unless you want to hang something from the centre of that centre beam I'd leave it alone.

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## Paulb007

I might put a light up in the center but thats about all. 
Thanks eveyone for your input, ill leave it be.   

> Looking at that looks very normal and would have been constructed to the engineered and approved specs. Unless you want to hang something from the centre of that centre beam I'd leave it alone.

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