Sovereign Group

Wood Preservation



There are several types fo guarantee available within the Timber Treatment Industry, some of which can be misleading. Insurance backed guarantees may in reality be 20 year Term Assured Guarantees, giving the underwriters the option, at the end of the Assured Term, normally 3 years, to refuse further cover for the remaining guarantee term. In this case a percentage of the original premium is returned, less as administration fee, for leaving the householder without cover.

However, since 1983 Sovereign has offered a 30 year Protection Scheme Guarantee for Timber Treatment. For a small premium of the contract price, Sovereign provides guarantee protection should the original contractor cease to trade, die or become bankrupt.


Where Timber Treatment is carried out by Sovereign Approved Contractors, then Protection Scheme Guarantees are available. Sovereign Approved contractors are available nationwide and can be located in the yellow pages either under Woodworm or Dry Rot or Damp Proofing, or by contacting our Head Office.

Training courses for operators, surveyors and Continued Professional Development are available for those associated with the indusrty. Contact our Approved Contractors Departement on:
Tel: 01229 870800
Fax: 01229 840870


This is issued by the timber supplier or manufacturing joiner to certify that the timber supplied for which anti-fungal treatment was specified, has been treated against fungal attack using Sovereign Wood Preservatives in accordance with B.W.P.D.A. requirements.

Sovereign Wood Preservatives and method of treatment conform in full to the B.W.P.D.A. requirements for the preservative treatment of timber as specified in:

  1. B.W.P.D.A. Manual 1986
  2. B.R.E. TECHNICAL NOTE 1967 (revised 1982)
  3. Registered House builders handbook.

Users of treated timber are reminded that the durability of timber is also dependant upon proper handling and installation.As we have no control over site conditions or installation, no further liability is accepted by Sovereign Chemicals Ltd.


Providing the moisture content remains below 20%, fungal attack will not develop.

This fungus causes decay primarily under conditions of restricted ventilation and high humidity, the optimum moisture content for decay being 25-40% moisture content.

Dry rot can remain active in timber down to 20% moisture and once established can attack dry timber. It can penetrate through brickwork and masonry and behind plaster, decaying any timber en-route. For the treatment of masonry / subsoil, the use of Sovereign Fungicidal Wall Solution should be considered.

DRY ROT (Serpula Lacrymans)

Dry Rot
Serpula Lacrymans
Fleshly soft plate. Yellow maturing
to red, white or grey margin.
Produces masses of red spores
which settle everywhere.
White sheets of mycelium with
patches of yellow/lilac especially
when exposed to light.
Also produces strands which are white
or grey up to 6mm thich. When
dried out becomes brittle.
Decays to dull dark brown,very light and
crumbles easily.Deep cracks along and
aross the grain with cuboidal cracking.
Often distorts shape of affected timber


There are many species of wet rot but all require relatively high moisture levels in timber (above 30%) for development. Unlike dry rot, any wet rot will not be restricted to areas of high moisture content.

Cellar Fungus
Coniophora puteana
Olive green/olive brown. Flat with
lumps.Rarely found.
Slender vein like. Yellowish but
brown/black when mature. May be
on timber or wallpaper or tile backing.
Most common fungal attack.Cuboidal
cracking which is often hidden under a
thin skin of sound timber.
White pore or mine fungus
Fibroporia vaillanti
Lumps,sheets or plates.
White/cream to yellow. Numerous
minute pores.
White/cream sheets or fern like
growths. The strands, white to cream
remain flexible.
General to softwood. Damage similar to dry
rot but timber is lighter in
colour and cracks are not as deep.
Donkioporia expansa Thin hard, brown or buff. Looks like
wood in layers with pores.
Yellow to red brown thick felted
growth. Follows contours of timber.
No strands.
Normally found on hardwood especially oak.
Timber becomes bleached and lint like.
Looks stringy with white fibres.

As the treatment of dry rot is more extensive and therefore more expensive than wet rot treatment, it is essential that correct identification is made.