Unsupported Purlin - can someone please advise? -NEW PICS-

[lowster]

I have recently purchased a 1965 chalet style bungalow (with front dormer) and was intending on putting a dormer to the rear, however, upon inspection I found that all Purlins are being supported by walls apart from one. There are 4 purlins in total and this is at the top to the rear of the bungalow. The width of the property is approx 30 feet and the purlin is in two pieces, bolted together in the middle spanning this entire length. It appears to have either sagged a little in the middle and is now resting on the horizontal beams below it which are nalied to the rafters (which I thought the purlin was supposed to be supporting??)


Can anyone tell me; is this normal to have a wooden purlin stretching this length (30 feet) unsupported? Or am I in trouble??!!


Cheers

 

[freddiemercurystwin]

Can you post a photo? Purlins usually span from gable to gable unsupported but are not normally created with two lengths of timber unless the connection is designed for the purpose. No offence but are you sure you're talking about purlins?

 

[lowster]

Hi, thanks for the reply. Yes they are definately purlins. They are supported by the gable ends and run the width of the house. I have knocked up a primitive sketch to show you what I mean. All purlins are supported apart from the top one shown in the pic which runs 30 feet without any support. It appears to have sagged a little in the middle and now appears to be resting (in the middle section only) on the beams that run between either side of the roof (nailed to the rafters.) I'm assuming that the purpose of the beams which are approx 2x2 is for the internal ceiling to hang from?

roof

• lowster
• 13 Apr 2011
• 1

 

[^woody^]

If the roof has not fell down since 1965, I'd hazard a guess that its probably OK

 

[lowster]

Here are pics of my dilema - Is this safe? Can I leave as is, or do I need to replace with a steel? The purlins are in two parts (joined in the middle) and are 9" x 3"

Untitled

• lowster
• 2 May 2011
• 1

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• lowster
• 2 May 2011
• 1

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• lowster
• 2 May 2011
• 1

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• lowster
• 2 May 2011
• 1

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• lowster
• 2 May 2011
• 1

Untitled

• lowster
• 2 May 2011
• 1

 

[lowster]

Can anybody put my mind at ease, please?!

 

[tkmax]

As Woody said, if it hasn't failed since the 60's it's probably ok. It looks like the ceiling ties are doing the job of stopping the rafters from sagging (although maybe not designed for this purpose) and the purlins aren't doing anything (which is good as they are way overspanned). If you really are worried because the roof looks out of shape generally then get a structural engineer to take a look.