A QUESTION OF ROT
Self service exercises in rot repair and treatment
Exercise 3 - Joist Ends
You are standing on the first or ground floor 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.
Floor boards laid over timber joists. The joists may be supported in the middle by a larger 'carrier' beam. Click here to see an example.
You notice that the joists look creased and lighter coloured where they disappear into the wall (wall socket or bearing). What other symptoms of decay or attack might you notice? Would these differ at all if the joists were made of a softwood (Pine) or a hardwood (say, Oak)?
What is causing the creasing and lightening?
How are you going to confirm that the cause is still present?
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 where could the cause be coming from?
How could these causes be eliminated?
How would you decide to what depth the timber is damaged?
Approximately what proportion of the timber can be damaged and surface repaired, without needing to cut out the section?
Is damage more important in one part of a Joist than another, from a structural point of view?
In some joists there is slight surface damage: when dug out the missing wood measures 1 inch (25mm) x 1inch (25mm) x 4inches (100mm). 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.
The end 1 foot (300mm) of 4 of the 8 inch (200mm) x 3 inch (75mm) Joists are beyond repair. Which timber repair technique could you use to replace them? Click here to see an example.
Which types of resin products are you likely to use?
What techniques could be used to cut slots or holes into the remaining timber, for connection to a new piece? Click here to see an example of slot cutting with a 3D Cutter. Click here to see an example of slot cutting with an Auger.
How much do you think the repair materials would cost? How long do you think it would take one man to cut out and replace one Joist End? Click here to see an Estimate and here for a Design.
What types of treatment could you offer, to minimise the risk of future rot?
What other measures might you take, depending on the types of floor and ceiling materials, to reduce the risk of rot and insect attack?
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
Course help - David Moore - 01626 331351 - email@example.com