Is timber rot contagious to other timber

happyhero

Hi I am into carpentry and have made all sorts and over the years I have built up a stock of timber. I was once given a lot of 3m scaffold boards as the company had to renew the ones they had, so I had the old ones, great loads of free timber. I put most of it under cover but some obviously got hit by the weather as it has sections of rot which I broke off and saw the rest is still solid, ie seems ok to use.

Recently I built a new shed with roof storage and moved all my timber into the shed roof resting on the treated roof timbers. When I did this I brushed off all the leaves and dust and what ever had rested on it over time so that I could store it away cleanly.

I now have it stacked in quite big stacks ie I would not want to get something from the bottom of the stack to often to save myself a load of shifting etc, but for some stupid reason I put the timbers that are damaged in places at the bottom resting straight on my treated shed roof joists/timbers with the good stuff on top.

Does anyone know, will the rot from the ones that have some rot cause damage to either my roof joists or the stored stacked timber? Could they have woodworm and being outside and if so I assume that could damage the stacked stuff as well but what about the treated roof timbers.

When I cleaned them one of them may have had some sort of mould growing on it, not sure as it was mucky and I brushed it all off.

I assume the rot would be damp rot as they were stored outside?

As I write this I think I can see you are going to go "Oh my God" and I fear I will have to unstack it all and get rid of a load of the bad stuff but anyway lets see what you tell me.

I realise I have probably made myself sound a bit silly here but I just really want to know a bit more about whether storing the rotten timbers for the good bits is going to cause me any problems.

Any help appreciated.

vaio

Dry rot (dryish wood with cracks along and across the grain, looks like little squares) is very contagious and can spread like the plague.

Wet rot (which is what I’d guess you have) is fine and as long as the stack is kept dry you’ll have no problems

David_Aldred

Hi,
Please see my post on this forum regarding 'woodworm' made the other week.

Dry and wet rot spores are present within the air all the time, that is to say they are ubiquitous and only require certain conditions to be met to promote rapid colonization. Primarily these fungus require oxygen, water, a certain temperature range and a food such as timber or timber based products. Where wood is plentiful the only thing that can be controlled is the water and if the moisture content of timber is kept generally below the threshold of decay (20-22%) the decay will not occur, or if it has previously occurred due to some moisture being present, if the moisture is removed to a level below 20% the decay will die out.

Chemical preservatives such as borons may be used as support measures during the drying down phase but only where deemed appropriate and never as a substitute to the main control measure of drying the timbers down to a point whereupon the decay will cease whether that decay be dry or wet rot.

Dry rot is fortunately relatively less common than wet rot given the former is more fussy over its conditions that it requires to flourish. The concern with dry rot is that its fungal strands are very invasive into the fabric of buildings. The fungus has a neat trick of being able to carry moisture along itself from a moisture source to wet ahead of itself areas that were previously dry thus ensuring continued growth.

From the above you will see that good cross ventilation to all the timber throughout be that the woodstacks or the shed itself is the key. Timber that is decayed and which you are unsure of whether is dry or wet rot should be cut out to at least 500mm beyond the last sign of infection and appropriately disposed of. The most vulnerable areas will be end grain exposed to significant moisture. Please google images for visual differences between wet and dry rots though be aware cuboidal cracking is common to both wet and dry rot and can easily be confused to those unfamiliar with what they are looking at.

Hope this helps, kindest regards, David Aldred Independent damp and timber surveyor.