Pergola repair advice

Wood working questions and answers in here please

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bparekh
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Pergola repair advice

Post by bparekh »

Hi

This post relates to an wooden outside pergola - I hope this is the best place to raise this.

I have a question about the construction of a pergola that I had built for me Feb last year which has now broken.
A few builders have given quotes on the repair, each stating a different methods so I want some advise on what is the best way forward. I wont be asking the original person back.

I am a basic DIYer and I may have ago myself depending on what needs to be done. Let me describe the current setup.

This is a lean to type pergola on my brick house. The pergola is all made of wood and was all stained with external woodstain before fitting.

There is a wooden wall plate, and 2.5 mtrs away three posts in the ground (postfix). Across the three posts is a girder (hopefully right definition)
All of this so far seems to be fine with no problems.

From the wall plate are about 8 wooden rafters going to the front girder. These rafters are 8in x 2in and have all failed and 2 have come away from the girder, so I have had to totally remove them for safety.

The rafters were fixed to the wall plate with pocket-hole type screw fixing (ie. at an angle from each side of the rafter going into the wall plate). At the wall plate end there are butted up to the wall plate, not notched in at all. All seemed to be safe and secure. At the girder end the rafters sit on top of the girder (not notched at all) and are also fixed to the girder with pocket hole type screw fixing (screwed to the girder on both sides of the rafter at an angle).
During the year the rafters have all twisted and warped. So at the girder end the rafters twisted and have come away from the girder (the screws have pulled out due to the twisting). I have fully removed these rafters for safetly.
Almost all the others have twisted as well - but at the moment seems to be secure enough...

When bought the rafters were 8x2 x3m lengths of exterior wood, tannalised and so were green in colour before the wood stain.

The last thing to mention is that during fitting I was asked if I wanted to see any metal fitting in the pergola or not. He told me he could build it without any visible metal fittings if I wanted to (ie no joist hangers etc). He suggested it woud look better. I chose build it with out the visible fittings. A mistake on my part I think...

I would like to have all the rafters replaced.

Some builders have said that problem is with the wood. I should have used constructional timber and then the fittings are OK and it would not warp. Replacing with constructional wood would sort it out. The fittings and other construction was OK and the new wood could be fitted like that again.

2 other builders said the wood used is OK but the fittings are incorrect. I should have noggings in between the rafters, and should have used better fittings to the girders (bolts were mentioed?) and maybe even notched the wood at the girder end. The pergolas I see online dont have noggings (noggings are more typical on lean-to type car ports etc) hence unsure about this part.

Both say the problems with be solved. The cost is not too different (the constructional timer is a bit more expensive to buy) but Im trying to work out what will work.

As its just the rafter that need replacing I could do the work my self and try and save a bit of money.
So some advise would be appreciated.

Many thaanks and apologies for the long post
bourbon
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Pergola repair advice

Post by bourbon »

If It was only done last February, get the original builder back. Photos would help here I think
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