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Ideal Dry Rot Conditions?

A wet winter followed by a warm summer means ideal conditions for the growth of the Dry rot fungi. A poorly maintained property, where excess water is permitted to enter the fabric of the building through the wetter Months, sets up ideal conditions for germination and often abundant growth of wood rotting fungi through the warmer Summer Months.

The long, wet Winter of 2012/13 through into the exceptionally long warm Summer of 2013 has seen a drastic rise in Dry rot enquiries to The Preservation Company and here is why:

Dry rot needs 3 elements to grow: AIR / WATER / FOOD

Water ingress is one of the major factors in producing an environment ideal for growth. If we use timber as an example of food; the spores land on damp timber, feed off the timber and “rot” the wood,. This eventually over time results in the complete breakdown of the structure of the wood, which could be your first indication of a problem.

Dry rot spores are always present in the atmosphere and simply need to find the right environment for germination.

Reddish brown Dry Rot Spores

Germinating spores produce hyphae (strands).  Like roots, the hyphae strands grow and then colonise to produce mycelium growth as shown below.

Dry Rot – “cotton wool like” Mycelium

If one of the 3 elements is then removed (such as the water drying due to a long hot summer),the Dry Rot becomes “stressed” and produces a fruiting body (sporophore), which sheds its spores into the atmosphere in an attempt to reproduce and continue the lifecycle and growth of the Dry Rot fungi.

 Fruiting Body / Sporophore

The Dry Rot fungi (Serpula Lacrymans) – Lacrymans means weep or cry to reflect the tear like droplets sometimes found in severe cases. As the following picture, taken recently, beautifully illustrates

If you think you have any of the signs of Dry Rot the most important thing is to act quickly. Dry Rot favours dark, damp conditions and is thus often difficult to locate (under floors and within roof voids). However once discovered , it can be readily eradicated simply by taking better control of your home environment, repairing any building defects that have contributed to the outbreak and of course the specialist use of timber and masonry preservatives and appropriate re-instatement works.

 

On the face of it

Like many old buildings, this central St Andrews property had suffered from minor yet long-standing damp ingress through a roof valley gutter. Slight damp staining to the wall plaster below and raised moisture meter readings led to our recommendations necessitating localised plaster and lath removals to expose concealed structural timbers.

Whilst the face of the timber safe lintel appeared sound and free from defect we, as experienced specialists, opted to investigate further. We insisted that the masonry adjacent to the lintel be removed and our suspicions were justified. The lintels are now removed and replaced in pre-stressed concrete.

An inexperienced eye may well have left the lintels in situ and, under the assumption that the roof valley repairs by a previous company would have dealt with the problem, this relatively localised wet rot situation could in fact have easily resulted in a large-scale dry rot attack. Not so!