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lean to front Porch - roof design and suggestion

Discussion in 'Building' started by Neil Pat, 9 Jan 2019.

  1. Neil Pat

    Neil Pat

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    Hi

    Im constructing a lean to porch and wondering if anyone can assist in the design i have

    The concrete foundation and 1 layer brickwork is already done.

    I will be using UPVC panels for the design as shown in the picture.

    My concern is the lean to roof. Currently the porch will have 2 corner posts which consist of upvc and aluminium insert.

    the rest of the porch is constructed with typical upvc.

    I plan to build a lean to roof out of timber frame and rafters sitting on the frame with redland 49 roof tiles. frame probably constructed suing 2x2 or 2x3 wood and same with the rafters.

    my worry is wood this be too much weight or this is what everyone does?

    the frame will be bolted to the wall so less weight falls on to the upvc panels\posts.

    Any help or ideas appreciated

    thanks
    Porch Blank Roof v2.jpg
     
    Last edited: 9 Jan 2019
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  3. Ian H

    Ian H

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    I did that on mine but the right side of mine was all brick and the left side 1/3rd brick.

    If I were you I would go OTT on the glass packing to make sure there is no sagging of the frames. Having said that, if you built the roof strong enough it would probably stay up if you removed the upvc.
     
  4. ^woody^

    ^woody^

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    You'll need reinforced corner posts for the porch frame, and the horizontal timber will act as a beam to keep the roof load off the frame. You still need to adequately fix the rafters to the wall to avoid them spreading.

    Alternatively, you could construct the roof as a series of mono-trusses which will largely cantilever off the wall with minimal loading to the porch frame.
     
  5. Neil Pat

    Neil Pat

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    Exactly what I was thinking that i would build it so that it will self self support it self.
    Thanks
     
  6. Neil Pat

    Neil Pat

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    Yeah the post will be reinforce aluminium steel. I'll put less stress on the upvc as possible

    Just trying to picture this... "roof as a series of mono-trusses which will largely cantilever off the wall "
    Is there any pictures you can point me too.

    Thanks
     
  7. Ian H

    Ian H

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    Imagine A load of triangles bolted to your wall
     
  8. Neil Pat

    Neil Pat

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    Cool, Think I get the idea , will try post pictures next week as the porch is arriving then, have ordered reinforced windows as well as corner post.

    thanks for all you help.
     
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  9. ^woody^

    ^woody^

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  11. Neil Pat

    Neil Pat

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    Perfect. Thanks. Exactly what I had in mind.
    Thanks
     
  12. catlad

    catlad

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    You could sheath the triangles with 12mm ply for strength.
     
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  13. What about a cavity tray , weep vents and lead flashing at the roof to wall abutment ?
     
  14. Neil Pat

    Neil Pat

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    Quick question on timber,

    the UPVC thickness is about 75mm

    what size thickness should my roof frame be constructed with?

    A 4"x2" will only be around 45mm thick, will that be sufficient?

    mind you i will need to drive screws through the upvc on to the frame above, so what thickness do people use?

    thanks
     
  15. noseall

    noseall

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    We have done this in the past, with the ply 'gusset' upright sitting hard against the masonry.
     
    Last edited: 20 Jan 2019
  16. noseall

    noseall

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    If the clear span of the rafter is around or less than 1.8m then you are fine with 95mm x 45mm.


    You will need to fix a sturdy bearer plate to the top of the frames first spanning from corner to corner then b/m your rafters onto this. Be careful with the fixings in terms of depth and not clashing with any ally reinforcing or hitting glass units etc. Stick it down with foam or polymer adhesive once you have pre-piloted it and had a dry run, first.
     
  17. Neil Pat

    Neil Pat

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    Thanks no seal
    I was just wondering the thickness is sufficient.

    I'll be constructing the frame work as per pic but rafters will sit on back wall plate which means cutting notchs out

    Should the rafters also be 4x2. Or would 2by2 will do?
     
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