A QUESTION OF ROT
Self service exercises in rot repair and treatment
Exercise 4 - Cracks, splits, shakes (along the grain)
You are standing inside the roof space of a building with the following tools: a torch, a tape measure, a 'damp' testing meter, a screwdriver, plus a pad and pencil.
(Use the attached form to make notes as you go and then compare them with the suggested answers). Click here for a copy of the Form.
Roof frames made of sloping members (rafters) and horizontal beams (ties, collars).
You notice that the horizontal Tie Beams have splits (called 'shakes') along the centres of the side faces. What other symptoms of distress or damage might you notice?
What is causing the splits?
How are you going to confirm whether the process has stopped or is still continuing?
Suggest the 'moisture meter' readings on which you might advise a Client as follows: a)no action required, b)at risk, needs treatment
Give as many examples as possible of why these timbers might have split in the first place.
How could these causes be eliminated in new build, renovation or repair?
How would you decide to what depth the splits extend?
Approximately what proportion of the timber width (thickness) can be split without needing to add reinforcement bars ('stitches')?
Is damage more important in one part of a Tie Beam than another, from a structural point of view?
In some Ties there is slight surface damage: the splits measure 1 inch wide (25mm) x 1inch deep (25mm) x 39 inches long (1000mm). What volume in cc's or litres of repair product will you need and what type of product could you use? Click here to see the product being mixed. Click here to see an example of the repair in progress.
If the splits are say 4 inches deep in a timber only 6 inches wide which timber repair technique could you use to repair and reinforce them? Click here to see an example of one step of the process.
Which types of resin and bar products are you likely to use?
What other measures might you take to reduce the risk of further splitting in this particular roof?
Click here to see the completed form. Suggest your own improvements to the answers.
Click here to see examples of this type of repair.
Click here to see examples of Boron based treatments that are suitable for this situation.
Next Exercise - click here
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