Forum home Garden design

Wooden greenhouse timber


Could anyone give me some advice on approximately what size timber would be suitable for a wooden greenhouse?

I'm not looking for exact dimensions (as this would depend on the overall size of the building) but at this stage just trying to get an overall idea of cost.

For the frame - particularly the supporting corner posts i'm looking at planed 50x100. Would appreciate knowing if this is in the right ballpark.



  • AnniDAnniD Posts: 8,235
    *Bump* in the hope that a construction expert can advise  :)
  • Allotment BoyAllotment Boy North London Posts: 4,079
    edited January 2020
    I am not a construction expert but I think 100 mm is a bit hefty remember all the beams will cut light. A lot depends on what timber you are going to use, the best timber greenhouses are made from red cedar which as well as being rot resistant is straight grained & strong. They are usually in sections so when joined the corners double up so to speak. The biggest timbers in mine are 35 x 70 approx most are 25 x40 though these are very approximate as the glass is rebated in so its hard to measure. For added strength  it uses metal angle brackets rather than big thick timbers. Hope this helps.

    Edited to add: In my experience by the time you buy timbers & all the screws brackets etc a kit is not so expensive, lots of firms are offering sales & discounts at this time of year too. So unless you need a very bespoke size or you already have the materials consider buying off the shelf as it were.
    AB Still learning

  • Thanks, that does help. I'm beginning to think 50x100 is too large. Was planning to go down to a couple of garden centres this weekend with a ruler!
Sign In or Register to comment.