Diagnosis Mérule Nord 59

 ​Why choose an independent firm  :

- for professional and impartial parasite identification, completely independent of companies specializing in curative treatment.

- for   an impartial opinion free of any interest, before scheduling renovation or treatment work.

 

Indeed to avoid being trapped by an unscrupulous practice which will probably become widespread soon. This is the attack of dry rot; fungus that likes to destroy wood. But, if at the outset the specialized craftsman, very open, announces to you, in person, dry rot, do not hesitate to contact our office. The result may pleasantly surprise you and thus avoid considerable costs that you are nevertheless told will be reimbursed by your insurance. The analysis is done immediately, advice is given to you.

Being an independent firm, there is therefore no conflict of interest.

You will thus have the assurance of undertaking the work strictly necessary for any attacks by parasites as identified by our technician.

 

We provide expertise and mycological diagnoses in the North 59-62 and these expertises can be doubly confirmed by a laboratory analysis. These expert opinions are admissible in court.

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Very often, I am asked the question of the admissibility of a non-contradictory expertise (expertise carried out without the presence of all the parties) before a Court.

Indeed, some ill-informed lawyers (and even some jurisdictions, sometimes...) maintain that only a contradictory expertise ordered by a judge would be admissible in court....

This is not the case, because the courts consider more and more often that the amicable (or party, or even unilateral) expertise is an admissible piece of evidence, it is up to the defendant to provide proof to the contrary by a possible counter expertise or the request for an order appointing a judicial expert for a contradictory expertise.

This is also a position that the Court of Cassation confirmed by   twice:
Also, from now on, all my expert reports include the following  mention:

"This unilateral expert report thus contributes to the exercise of the right   to prove your damages. The Court of Cassation has recognized the admissibility of the unilateral expert report as evidence.
(Cassation: Civil Chamber - Judgment n°412 of April 5, 2012 - Mixed Chamber - Judgment n° 271 of September 28, 2012)"

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rotting mushrooms

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Several fungi are capable of devastating your frames, stairs, floors or joists in just a few months. These fungi, called “lignivores”, belong to many species present in the atmosphere in the form of spores. It is enough that all the conditions are met, during a more or less long space of time, for these organisms to take shape and begin their destruction of timber. The most commonly encountered bear the common names of Mérule, Coniophore, Lenzite or Polypore.
The ultimate phase of wood degradation by fungi is rot. Three main types of rot are to be considered depending on the element of the wood used: cubic or brown rot, fibrous or white rot and soft rot.

Dry rot
The Coniophore des Caves
Beam Lenzite
Cellar Polypore
Soft Rot

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Dry rot

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Dry rot is a cubic rot fungus. Its name, derived from the Greek "merizo" (to divide, to fragment), recalls the fragmentation of the wood that it causes. Some have used the name in the masculine, gender of the Latin name given to it in the last century, but the use of the feminine has been applied to it for a long time and by renowned mycologists.

The vernacular names encountered in France are "merule", "merule weeping" because of the colored tears exuded by its mycelium or "merule of houses".
In fact, the name "Merule" is made up of several species of fungi. We will present to you, here, the one that concerns us the most, because the most frequently encountered in our latitudes and also the most devastating: it is Serpula lacrymans.

This wood-eating fungus, very cosmopolitan, only attacks timber, especially conifers but frequently hardwoods as well.

Serpula lacrymans is found in temperate zones throughout the northern hemisphere. Its appearance is in fact closely linked to the humidification of the wood. Moreover, if the atmosphere is confined, its growth will be favored.

The development of dry rot breaks down into 2 phases:

•Vegetative formation: the germination of the spore produces a white fluffy mass which can reach 5 to 50 mm thickness and which can take, under a diffused light, a canary yellow color. This is the primary mycelium. By fusion of mycelium from different spores, a very abundant white mycelium is formed because of vigorous growth, the secondary mycelium.
According to the favorable environmental conditions and according to the nutritive nature of the substrate, this mycelium evolves in format or white fluffy masses sometimes very voluminous up to several cubic meters or more or less thick cushions, generally from 2 to 4 cm in diameter. thick, passing to yellow, green, pink or purplish and acquiring with age a more tenacious surface of ocher or gray tint.

Fresh mycelium usually has a pleasant edible mushroom smell, but is bitter in taste and poisonous.

It is in the mycelium that increasingly thick, branched, cylindrical or flattened mycelial cords are formed, improperly called "rhizomorphs".

 

•The fruiting stage: Serpula lacrymans is a sexual fungus. From the reproduction of two individuals will be born a new mycelium which will produce one or more fruiting bodies or carpophores. Of varied shapes, more or less spread out, being able to extend from a few centimeters up to almost 2 meters and of brown-rusty to yellowish colors towards the edge, the carpophores are flattened on the wood. The fertile surface is wrinkled, honeycombed and composed of microscopic spores present by the billions serving to reproduce the species by dissemination.

Examples of the 2nd phase of Dry rot "Fructifications"

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Development requirements:
• Wood humidity: dry rot develops in humidity between 22 and 35%. At 35% humidity, its development is very rapid. Beyond 40%, it ceases its development.
• Temperature: dry rot develops between 7 and 20°C. Its development is optimal between 20 and 26°C, especially in a confined atmosphere. However, it is not resistant to higher temperatures.
Great darkness is required for the vegetative phase.
The fruiting phase requires a minimum of light to flourish.
Note the particular role of the cords used to transport water and which can cross walls and masonry over several meters.
Dry rot actually represents about 70% of damage cases inside buildings in Northern Europe.

By digesting the cellulose of the wood, the fungus releases water which increases the humidity of the wood and accelerates the attack. The hydrolysis of the cellulose results in a brown coloring of the wood as well as a cleavage following the three rectangular planes. The consistency of the wood becomes dry and brittle. This is called "cubic rot".

Examples of Dry rot Damage

 

The Coniophore des Caves

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The Coniophore des Caves is also a cubic rot fungus. The scientific name is Coniophora puteana.
This species attacks very humid wood with a minimum water content of 30%, a content higher than that admitted by Serpula lacrymans.
It develops easily in the dark and especially in the cellars of houses or the holds of boats.

The development of the Coniophore des Caves takes place in 2 phases:
• Vegetative formation: the mycelium is yellow-white, fluffy, but becomes more sparse in a dry environment. As it ages, the mushroom darkens and turns rather brown with age. it produces very fine cords of brown then blackish color. The consistency of the coniophore des caves is soft.

Examples of "Vegetative Formation" of the cave coniophore

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Appearance of brown cords

• Fruiting bodies: fruiting bodies are rarer inside the building than outside, due to the instability of the high humidity conditions necessary for their development. They appear in the form of continuous membranous crusts, marrying the surface of the substrate, of irregular outline, which can measure from 1 to 30 cm, with a brown-ocher to brown-purple surface and a white to yellow-brown periphery.

Development requirements:
• Humidity of the wood: the coniophore develops in a minimum humidity of 30 to 40% Its development is optimum if the humidity is between 50 and 60%.
• Temperature: The optimum temperature for its development is 24°C and should not exceed 35°.

The cords develop on the masonry, but do not intervene in the transfer of water.
In the botanical sense, the coniophore des caves is very close to the dry rot. It can be confused with the latter. But given its moisture requirements, it is much less common.
It also attacks softwoods as well as hardwoods.

 

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Beam Lenzite

Beam Lenzite whose scientific names are Lenzites separia (Wulf.) Fr. or Gloeophyllum sepiarium (Wulf.). Karst are part of the "Brown cubic rots".

This wood-eating fungus, which is always encountered in the open air, is able to easily resist alternating humidity and drought. This fungus degrades fences, posts, bridge piers and exterior glulam.

The development of the lenzite of the beams breaks down into 2 phases:
• Vegetative formation (mycelium): The fungus during this phase is yellow or brownish in color. It appears in cottony masses.
• Fructifications: In this last phase, the lenzite of the beams is yellow or orange when fresh. We can see consoles of small sizes with a fluffy russet upper face. On the underside the blades are yellow. The latter can be contiguous and form regular tubes.

Development requirements:
The lenzite of the beams is very tenacious. It resists humidity below 20% in dry wood and can even grow at very high humidity levels (over 50%!).

It is the most common wood-eating fungus in France. It is common to find it on softwoods and also on exterior lumber.

This fungus particularly likes all resinous species (sapwood and heartwood) which decompose when attacked. Lenzite from beams rarely attacks hardwoods, but hardwoods are not excluded.

At the beginning of the attack the wood is yellowish. We also see a cleavage according to the annual rings of the wood. The cutting is according to the three rectangular planes. Like the dry rot, the lenzite of the beams is part of the "cubic rots".

 

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Cellar Polypore

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The Cellar Polypore whose scientific names are Donkioporia expansa Desm. or Phellinus megaloporus (Pers.) Hein are part of the "white fibrous rots".

This wood-eating fungus is mainly found in homes. It is mainly found on very humid hardwoods, especially on oak.

The development of the cellar polypore is broken down into 2 phases:
• Vegetative formation: It appears as a clump of thick felty white mycellium in the form of pads which turn yellowish as it ages. It then takes on a leathery and hard consistency. Unlike dry rot, for example, this fungus does not form cords.
• Fruiting bodies: The fruiting bodies develop on top of the vegetative forms. They are irregular, brown nipples, formed of long, thin tubes and sometimes arranged in stratified layers.

Development requirements:
Its development requires very high humidity levels, above 40%.
Also it requires a relatively high temperature, above 25°C. Its development is fastest when the temperature is around 35°C.
This fungus only grows in dark, poorly ventilated places and where the wood is covered.
It grows slowly as a rule.

In France, the cellar polypore represents 30% of the cases of damage observed in buildings. Hardwood frames are the most affected.

Hardwoods (oak, chestnut) are the woods most often attacked. Heartwood decays faster than sapwood.
It is quite rare for this fungus to attack softwoods.

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Soft Rot

The most common representative of Soft Rot is Chaetomium globosum Kunz.

The fungi causing "soft rot" are particularly prevalent in wood in contact with the ground, the slats of industrial refrigerants and possibly exterior joinery subjected to abnormally high humidity levels causing a significant loss of mechanical properties.

The attacked wood appears softened and has a spongy appearance. The soft rot is blackish in colour. We also see a regular cutting of the wood in 2 perpendicular directions after drying.

Development requirements:
This fungus develops for very high wood humidity (above 50%).
The optimum temperatures for development are between 25 and 30°C. Soft rot is resistant to high temperatures (50°C).
The presence of mineral salts accelerates the degradation of wood in contact with the ground or on cooling towers.

The woods attacked by soft rot are hardwoods (oak sapwood, beech) which are degraded in depth. But it also attacks resinous wood whose degradation is less intense and more superficial.

Soft rot therefore attacks in very specific conditions.