What is dry rot

Dry rot is a wood-decaying condition that compromises the structural integrity of affected wood members. This condition in all cases is caused by moisture and water. Dry rot is actually the result of a fungal infection that infects the starch within the cellulose of the wood components.

The prerequisites for the fungus to develop and cause rot, are moisture exposure and warm temperatures. Keeping exterior wood members sealed from the rain and uncontrollable weather elements will help protect your home from dry rot and water damage. Here in Sacramento CA, we don’t get a lot of rain, but due to the dry weather, most homes run their garden sprinklers every day. If the sprinklers overspray onto the structure with wood components, then dry rot will start developing and continue to grow even in the hot summer days.

Some areas of Sacramento, along with the river delta, struggle with high water which means that the soil under the home stays wet throughout the year. This condition can lead to excessive moisture levels in the sub-structure (crawls spaces) that accelerates the growth of fungus and eventual dry rot at the structural framing members. If you own a home along the river in areas such as Fair Oaks, Rancho Cordova, Folsom, Downtown Sacramento or Elk Grove, then inspecting your substructure for wet soil is highly recommended. In most cases, proper ventilation will resolve the issues with moisture presence and help prevent expensive dry rot damage.

Some of the other common areas for rot development are bathroom floors (tubs and toilets), roof eaves, siding, and decks. Here at Rot Repair, a branch of Good Life Construction, we offer free estimates for any dry rot or water damaged wood repairs that you might need.

Types of rot: what is the peculiarity of wood damage

Rot – color-abnormal areas of wood with a decrease in hardness that occur under the influence of wood-destroying mushrooms, of which one of the most dangerous is a real house mushroom. The grade of wood affected by rot is reduced to its complete unsuitability. In accordance with GOST, rot are classified:
by color and structure of the affected wood:
variegated sieve rot, or rot (unofficial) – yellowish spots and stripes with a cellular or fibrous structure are present on the reddish-brown or gray-violet background of the affected wood; the affected wood maintains integrity for a long time, with strong destruction it becomes soft and easily split. In a felled tree, its further development stops;
brown fissured rot – has a fissured prismatic structure, sometimes contains whitish or yellowish mushroom films in cracks;
white fibrous rot – wood acquires a white color and fibrous structure. With severe destruction easily breaks. It is found on hardwood;
marble rot – the affected wood acquires a marble pattern in which light areas are limited from darker black curvy lines.
by type:
sapwood rot:
sound rot – characterized by reduced hardness;
external rotting rot – brown fissured rot, occurring mainly in the outer, both in the sound and sapwood parts of timber, covers it along the entire cross section or only along its part and extends inland, often along cracks. Mushroom cords and fruiting bodies are often observed on the surface. May continue even in relatively dry wood. Affected wood is a source of danger to entire wooden structures.

Fungal infection of wooden structures

Mushroom lesions of wood

Wooden structures, subject to dampness, are susceptible to fungal infection. On untreated surfaces, in humid conditions, the spores of the fungus multiply until they destroy all the wood.Mold is a fungus whose destructive activity is manifested in the form of black spots on wood, plaster or wallpaper, sometimes it appears in the form of white hairy formations.

If you erase the stain or clean it off, then there are no traces left at the place where the fungus grows, i.e. it is necessary to eliminate the causes of dampness, treat the infected area with a fungicide or a warm solution consisting of one part of household bleach and 16 parts of water.

Wet rot

Infection with fungus, manifested in the form of wet rot, occurs only in wet wood. The development of wet rot stops when the moisture source is removed.

When rainwater enters the connection between the brickwork and the adjacent wooden parts of the door and window frames, wet rot develops.

Peeling paint is the first sign of rot.

When removing paint, the unsightly appearance of the wood opens – it is dark brown, crumbling when dry, or porous and soft when wet.

When the fungus comes into full force, at later stages – the wood is stratified, dark brown or black strands of the fungus are clearly visible.

Conclusion: if you find wet rot – start practicing without delay.

Fungus – dry rot

The fungus infects wood at a much lower moisture content than wet rot, but only in dark, poorly ventilated places and if dry rot has settled in wooden structures, urgent countermeasures are needed.

This fungus can lead to serious consequences of wood damage.

Dry rot spreads with the help of thin tubular strands or fibers very widely, it even passes through cracks in plaster, stone, brick and concrete.

In this case, infection develops very quickly – up to 150 mm. per month. If dry rot settles, fixing, it forms a wrinkled pancake-bearing fruit-bearing mushrooms of brown color, with smooth, white outer edges.

Rot is capable of throwing out spores, they cover the surrounding wood and brickwork with a layer of fine dust of red-rusty color, a strong smell appears, similar to mushroom.

Wood infected with dry rot becomes dark and brittle, cracks appear along and across the fibers, the result of the fungus is the breaking of the tree. At the same time, painted wood can warp and fail.


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