Course help - David Moore - 01626 331351 - dcmoore@timber.org.uk

YOUR ANSWERS TO ROT
Exercise 5 – Boron based treatments

You have found some damp timber. You have to decide what treatments to use

What you can see

Roof frames made of sloping members (rafters) and horizontal beams (ties, collars) and their bearing ends (in the wall) all show signs of dampness (stains, darkening).

Checking for defects

Q. What other symptoms of distress, damage or decay might you notice?

A. Signs of Mould, Wet Rot or Dry Rot – skin (Mycelium), strands, fruiting bodies, cubing, cracking

Look for the cause

Q. What is causing the dampness?

A. Original moisture content of the timber, penetrating dampness, water leaks or condensation

Q. How are you going to confirm whether the process has stopped or is still continuing? 

A. Comparative moisture meter testing, use of Dew Tabs (condensation testing)

Q. Suggest the 'moisture meter' readings on which you might advise a Client as follows: 

A. a) no action required – below 16%

A. b) at risk, needs treatment – above 18%

Q. Give as many examples as possible of why these timbers might have become wet in the first place.

A. Original building used ‘green’ or unseasoned timber, or subsequent water leaks, plus hot cold cycle causing condensation due to poor ventilation, excessive ceiling insulation. 

Q. How could these causes be eliminated in new build, renovation or repair?

A. Use seasoned or Kiln Dried (KD) timber, breathing roof felt, warm roof system.

Assess the damage

Q. How would you decide to what depth the dampness extends?

A. Take moisture readings at depth,use an Auger and look at the chippings

Q. What specialist surveying tools could you use?

A. Use deep wall electrodes or timber hammer electrodes

Q. Why is treatment to depth necessary?

A. To stop rot developing, to reach insects boring deep inside (like Death Watch Beetle in Oak)

Offer a treatment

Q. Which types of Boron based products are you likely to use?

A. Gel, Paste and Rods

Q. What other measures might you take to reduce the risk of future decay?

A. Improve roof ventilation.

Course help - David Moore - 01626 331351 - dcmoore@timber.org.uk

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