DRY ROT - SERPULA LACRYMANS
Why An Estimated Price For Dry Rot Eradication?

As explained, dry rot has the ability to penetrate and extend its growth into the places that cannot be clearly seen prior to ‘opening up’ the affected areas. Consequently, it is often standard procedure to estimate the cost of dry rot eradication rather than provide a fixed sum quotation.

Where major outbreaks are concerned, to carry out a complete and thorough inspection will take a considerable amount of surveying time.
Unfortunately, there are a number of contractors who will carry out a relatively quick inspection, provide a report confirming dry rot to be the problem and submit a ‘low' estimated price for the initial works.

All works additional to those included in the initial estimate, will then be charged extra to the original price. Once a contractor has begun work under this arrangement their client is virtually trapped into allowing them to complete the works, despite often alarmingly escalating costs. The advantages to this type of contractor are a comparatively much lower and apparently more competitive, original ‘quotation’ and the sure knowledge of further works at advantageous prices.

There are occasions when it is not possible to fully assess the extent of the dry rot outbreak due for example; to the construction of the building, premature disturbance of the decorations, or adjoining areas being completely inaccessible at the time of inspection. In such circumstances close liaison with the client should take place to explain the difficulty in assessing final costs.

Following an initial thorough survey Rudders & Paynes surveyors will, where necessary, meet the respective client at the building affected and explain the problems found. It will be at this meeting that a full explanation will be given as to the work covered in our initial specification and base quotation. If appropriate, any further areas causing concern that were inaccessible will be identified at this time. In this way our respective client will always know what works is offered and at what cost.

In the greatest majority of cases it is possible for our professional surveyors to provide an estimate that is accurate or very close to the final cost of remedial works.

New Methods For The Treatment of Dry Rot?

In recent years there has been an increasing trend towards the eradication of dry rot without the use of fungicides. As explained earlier, for growth to develop, dry rot needs moisture to be present in the timber and other elements of the building structure.

It is also sensitive to high temperatures. These two growth characteristics have been used as the basis for some new and unconventional approaches to treating dry rot. Developed mainly in Denmark, the new methods involve heating walls, structural timbers and embedded timbers in buildings affected by dry rot.

The new techniques use ‘heat treatment’ to kill any dry rot growth present and eliminate the source of moisture. There are currently two techniques in commercial use. The temperature is raised in part or the whole of the building to around 60°C, (lethal to dry rot) and maintained for a period of time, sometimes days. This is achieved using hot air/gas, which is blown in over 24 hours or more. For this treatment to be carried out the area to be isolated or the whole building will need to be emptied of all furnishings, carpets, etc. and substantial temporary insulation has to be installed to retain the high temperature needed.

The other method involves the use of microwaves to heat timbers to temperatures lethal to dry rot. This method can prevent the need to remove and replace timber where its structural strength is still sufficient to allow it to remain.

Both methods, whilst destroying the active growth, also aid the drying out process which is essential in dry rot control. However, there are certain drawbacks. Destroying the fungal growth using applied heat techniques offers no long term protection against re-infestation either during the drying out period, which may still be many months, or in the future. Large areas, or the whole building, may have to be completely vacated whilst the heat is applied and maintained for the prescribed duration, which can be several days.

Other so-called 'environmental' methods of dry rot control are advocated without heat or preservative treatment. These involve drying out over long periods by leaving damp areas open; use of humidifiers etc. and with the additional burden of monitoring affected areas to detect any return of dry rot during the drying out period. Such methods are unsuitable for most property owners who additionally must bear the risk of return of dry rot whilst the building dries out and there is no residual protection of reinstated timbers.

Rudders & Paynes, having considered these new methods, recommends prudent use of approved preservative treatments, in accordance with the BWPDA Code of Practice and as specified by our qualified surveyors.