How do I fix this sagging pergola?

PilgrimToHyperion

PilgrimToHyperion

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I wanted a pergola at my house so a friend I know (carpenter) helped me build this:



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Very happy with the result. Decided to plant a virginia creeper which has grown beautifully over the last 3 years, but I've noticed that the pergola has started sagging in front:

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It's definitely not only the weight off the plant. The pergola started sagging when this plant was still growing toward the top of it.

More pics:

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I'm worried that this will break and damage the property or kill someone. I'm not keen on putting a support pillar in the middle of the stoep. What are my options? I believe cables might be one but won't it pull down the wall they're anchored in?

Thank you for weighing in.
 
Pretty clear it needs more support in the middle.

Couple of options in my limited experience.

  • Centre support pillar as you have already mentioned
  • Improve how secure that mitre joint is
  • Beef up the size of the beams running from pillar to pillar
  • Add in a wooden corner brace on the pillars, something like the below
 

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Not a carpenter, just like watching how mostly Americans build their houses with wood.

Natural wood bows in a certain direction. Normally the contractors, will align the bow in one/same direction/orientation to avoid any issues. Secondly was this untreated/raw wood or treated wood. Raw wood will dry and shrink with time, there is specific techniques used to account for this.

Carl Rogers - works on restoring an old barn exclusively with raw untreated oak, see his techniques: https://www.youtube.com/channel/UCC76FBg2d-5NWFD8aK4ql5A

Perkins Brothers do explain some of their approaches but it is not in any specific video, there might be some insight there: https://www.youtube.com/c/PerkinsBuilderBrothers

My approach would be to laminate the beam on which your rafters are resting on. Triple up or quadruple it. This is what the contractors do when they have a long beam supporting alot of weight, the strengthen the beam by adding more beams so that the weight can be shared. Then add a corner brace.

To give you idea on how corner braces work:

This advice comes purely from watching Youtube:cool:
 
Aesthetically pleasing fixes are, as already mentioned:

Replace the main support beam with a laminated beam.. the current beam is supporting too much weight for the distance it stretches unsupported, which leads me to the next alternative:

Two support posts either sides of the steps..
 
Easy fix. All you need is a reinforced angle iron to support the front beam.
By reinforced I mean a full length of 6m steel plus another length of say 2 metres in the middle. The 2 angle irons must be bolted/welded together through the timber.

An another across, half way going to the back.


You don't an unsightly pillar in the middle
 
WaxLyrical said:
Easy fix. All you need is a reinforced angle iron to support the front beam.
By reinforced I mean a full length of 6m steel plus another length of say 2 metres in the middle. The 2 angle irons must be bolted/welded together through the timber.

An another across, half way going to the back.


You don't an unsightly pillar in the middle
Click to expand...

The rafters are in the way, so you cannot bolt the angle iron to the back of the main support beam..
 
WAslayer said:
The rafters are in the way, so you cannot bolt the angle iron to the back of the main support beam..
Click to expand...
From the pic it looks like the rafters were "clipped" onto the main beam. And then brandering bolted onto the rafters so all weight is now on the centre of the beam leading to the sag.

The rafters need to be trimmed at the clip on spot to allow for a metal angle to fit.

Alternatively a wide but thick flat bar from the front can be considered and then painted to match the wood.

It's hard to tell with the pics but this is my estimation.
 
Beam is to thin for the span. Also assume the posts are not bending?

1. What is the size of that structural beam(s)?
2. What is the span from post to post?


Then double or triple up on the beam.

Also how are those cross beams notched?
Did they cut out the notches from the structural beam? Maybe the beam has been structurally comprised.
 
Suspend it.
Pergola.png

You can run another piece of flat iron from the apex of the curve towards the wall and bolt it in, will give extra stability and virtually unseen with all that foliage.
 
The support pillars are also bending in and that creeper is going to get real heavy real fast. I'd do the bolted steel reinforcement across the front, corner joists AND pillars either side of the steps. As well as cables from the centre of the pergola into the wall
 
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