Hello everyone,
Two years ago, we had a pergola built by an acquaintance.
The pergola is located on the terrace and measures 4m (13 feet) wide, 4m (13 feet) long, and 2.5m (8 feet) high.
The back part of the pergola is mounted to the house wall, making it very stable with no wobbling. However, the front part feels wobbly when the pergola is moved sideways or when the wind is strong. I believe this stress won’t be good in the long run, especially since the concrete foundation only uses U-post anchors for fastening.
As shown in the sketch, only the two vertical posts and the horizontal beam are present (filled in blue), so there are no diagonal braces!
In my opinion, the structure is not well supported, which causes stabilization problems. We especially noticed this when we hung a swinging chair. When swinging parallel to the house, the pergola moves along! Swinging toward the house does not cause movement, as the attachment to the wall is very stable. Mistakes were made, and now we need a solution.
1) What do you think, would installing two diagonal braces on the right and left sides (green in the sketch) be enough to provide sufficient stabilization? If yes, how long should these braces be? Is there a rule of thumb? For example, for a size of 4m by 2.5m, should the brace be mounted about 50cm (20 inches) from the wood post? What type of fasteners should be used, and what is the best way to attach them? Are there other important factors to consider?
2) While researching, I found another pergola design that included a center post (marked in red in the sketch), which would of course help. However, we would prefer to keep the space open since there is a beautiful hedge behind it, and the post would obstruct the view of the garden.
Would just option 1) be sufficient?
Do you have any other suggestions?
Thank you for your help.
Best regards
Two years ago, we had a pergola built by an acquaintance.
The pergola is located on the terrace and measures 4m (13 feet) wide, 4m (13 feet) long, and 2.5m (8 feet) high.
The back part of the pergola is mounted to the house wall, making it very stable with no wobbling. However, the front part feels wobbly when the pergola is moved sideways or when the wind is strong. I believe this stress won’t be good in the long run, especially since the concrete foundation only uses U-post anchors for fastening.
As shown in the sketch, only the two vertical posts and the horizontal beam are present (filled in blue), so there are no diagonal braces!
In my opinion, the structure is not well supported, which causes stabilization problems. We especially noticed this when we hung a swinging chair. When swinging parallel to the house, the pergola moves along! Swinging toward the house does not cause movement, as the attachment to the wall is very stable. Mistakes were made, and now we need a solution.
1) What do you think, would installing two diagonal braces on the right and left sides (green in the sketch) be enough to provide sufficient stabilization? If yes, how long should these braces be? Is there a rule of thumb? For example, for a size of 4m by 2.5m, should the brace be mounted about 50cm (20 inches) from the wood post? What type of fasteners should be used, and what is the best way to attach them? Are there other important factors to consider?
2) While researching, I found another pergola design that included a center post (marked in red in the sketch), which would of course help. However, we would prefer to keep the space open since there is a beautiful hedge behind it, and the post would obstruct the view of the garden.
Would just option 1) be sufficient?
Do you have any other suggestions?
Thank you for your help.
Best regards
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