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Partially worm eaten joist ends

Discussion in 'Wood / Woodwork / Carpentry' started by kez1, 28 Jan 2019.

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  1. kez1

    kez1

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    3 old pitch pine joist ends are partially worm eaten at the sides. It's not bad and appears to be shallow only.
    Easiest to do is double up and bolt ons without chopping off wormed ends.
    Then again worm may not be dead, though my feeling is it is.

    Can I somehow treat in place wormed ends in reliable way?

    Can anyone recommend joist DPM boots?
     
  2. JobAndKnock

    JobAndKnock

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    Without exception you should always remove decayed joist ends simply because they act as a sort of reservoir for insect infestation and fungiis. There is no way to adequately treat timbers in situ, at least not for a DIYer

    Your sistered joist ends need a minimum of 1 meter overlap (ideally longer) with a minimum of three bolts, secured with square washers and nuts. Between the joist and the repair piece you need to have a star washer on the bolt. Cut ends need to betreated with preservative

    There are various techniques for dealing with the ends. An old technique used to be to dip the end in hot tar or bitumen, whilst others favoured (now banned) creosote. On repair works where we've done these in recent years, however, the approach has been to resin anchor bolt a pitch pine or sometimes a pressure treated ledger plate onto the wall and then use joist hangers off that. In areas below ground level where the walls could contain damp and in that instance we often put a layer of DPM between the wall and the back face of the ledger plate to reduce moisture ingress. The reason for using a ledger as opposed to re-inserting timbers into the holes in the wall is two-fold - firtsly the new sistered joist ends don't line-up to the holes, and secondly those sockets in masonry tend to trap moisture and start off rot far earlier
     
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  4. kez1

    kez1

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    Thanks.
    I'm going to cut them off.
    Thinking to blackjack (bitumen in white spirit) ends and sit on DPM base.
    Clearly wall has been damp though not below ground level.
    Know what you mean about plates and being no holes - this is not a problem here as joists sit on wall edge and there is plenty room for staggered double up/sister.
    Where do you get the parts for the wall plates. If you have a diagram of how you mount the hanger on plate that would be very handy.
    Many thanks
     
  5. JobAndKnock

    JobAndKnock

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    Joist hangers in many sizes come from firms like Armstrong Strongtie and are generally available though good builders merchants, trade ironmongers, some timber merchants and the like. They are always full nailed (i.e. a nail in every hole) onto the ledgers using square twist nails and never, ever screwed on. They are a simple surface mount, nailed through
     
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