Termite Time


Termite TimeIt’s the time of year when termite colonies become active. While pests such as woodworm spread relatively slowly, termites work fast and can rapidly cause damage to building timbers and other elements  as well as furniture, shoes, paper (e.g. stored books) and even food.




Detection:-Termites can initially be difficult to detect as they will normally tunnel from ground level between structural elements, e.g. between render and blocks, where render key has been lost creating access to higher levels, where timber (their usual food source) can be found. They will then typically attack the timber from behind, again using the junction between the wall and for example a doorframe, to continue their access tunnels. In nature they would access a tree between the wood and outer bark. Any situation where this narrow protected passage of access occurs in buildings, is likely to allow for termite infiltration. Initially it might be difficult to work out how termites have scaled a shiny tiled bathroom or kitchen wall to attack a window frame, but normally removing tiles below the window would expose a dry mud like tunnelling route between the wall and tiles from ground level. Even when in the timber, detection can still be difficult as they are skilled at munching away all the sub timber without breaking through the outer surface e.g. varnish film. Often, once signs are visible e.g. wood is discoloured or surface is blistered, the infestation can be extensive. A glance around a house is therefore rarely sufficient when it comes to spotting termites.
Unfortunately unless inspection is carried out before purchase, the first sign of infestation can occur after people move into a property. Once lying in bed at night or sitting quietly reading, they may find they are not alone, as the busy termite activity can be heard, as literally thousands of culprits run around the network of tunnels, and eat away timbers. As well as structural timbers, door and window frames, the rear of furniture adjacent to walls, kitchen units, and hanging pictures are favourite nesting spots for termites, some of which do not require a connection to earth or a water source, and are hence, pretty self sufficient, provided that they have enough wood (picture frame or side board!) to eat.
Exposure of tunnels by breaking away surface wood, will normally reveal the busy termites themselves Reticulitermes  (a little like a large headed white ant, see photo).

Termite Types

Worldwide there are many different termite types, (spread is easily through imported timber) but Spain is mainly subject to the following:-

 

Dry wood termites infest dry, sound wood, including structural timber, as well as dead limbs of native trees, fruit trees (cherry and almond are common targets), utility poles (that’s why the new timber ones are often set on a metal spike), posts, and stored timber, especially when in contact with the ground (Infested log piles often reveal that termites are very close by). From these areas, winged reproductives seasonally migrate to nearby buildings and other structures, usually on sunny days during summer and/or autumn (migration has just started). In their winged form the termites look like flying ants (growth stages pic), then the lucky ones fall in love, shed their wings and seek timber for their honeymoon (staring a new infestation). Dry wood termites are most prevalent in many coastal and arid locations.  Dry wood termites have a low moisture requirement and can tolerate dry conditions for prolonged periods. They do not connect their nests to the soil. Piles of their faecal pellets, which are distinctive in appearance, may be a clue to their presence.

           

Subterranean termites require a source of moisture in their environment.  To satisfy this need, they usually nest in or near the soil and tend to reach their food sources from the underlying soil.  They maintain some connection with the ground through tunnels in wood or through shelter tubes that they construct. These shelter tubes are made of soil with bits of wood and termite faecal material.  Termites readily chew through a number of other materials including plasterboard (drywall) and plastics (polystyrene insulation against a concrete slab provides a surprisingly hospitable access route for them).  The most significant damage they cause occurs in foundation and structural support wood, therefore it makes sense to ensure that new properties are raised half a meter or so above ground. Care can then be taken in constructing plinth to ensure that access voids are eliminated. e.g. claddings should be stopped before contact with soil and well bonded to the substrate e.g. with the addition of a non-corrosive mesh. A raised stone faced concrete plinth is especially advisable for timber houses. Fortunately, modern Spanish construction (the last 35 years) tends to be relatively termite proof from a structural point of view as concrete slab floors, concrete beams and concrete or block columns are not directly affected (the average British house would be the perfect nesting site for termites), however any untreated or poorly treated timber is highly likely to eventually be accessed and attacked via voids in the otherwise sound structure. While we are more fortunate in Spain compared to some countries, in that termite attack to newer properties is often more cosmetic here, older buildings are at risk of complete structural failure, due to underlying termite and other wood boring insect attack and should be checked thoroughly.

Termiticide applications are particularly challenging in Europe due to high density of buildings, type of construction, and historic age of many buildings.  Some treatments are designed for the soil surrounding and beneath a property, while others are periodically added to monitoring and baiting points (the termites are attracted to untreated wood placed in the baiters, which are regularly checked, if attack occurs this is then replaced with bait which the termites carry on through to the nest). There is always a risk that an airborne infestation could occur, therefore the most important prevention technique is via proper treatment of all timbers, boards, furniture etc within the property.
The spray type ‘carcoma’ treatment (normally used for wood worm) will kill live termite infestations where exposed, and normally prevent further attack in the immediate treated area. Always try to spray the infestation throughout removal, to prevent termites from spreading to other parts of the property. New treated timber can be spliced in e.g. to the affected lower portion of a door frame, and minor damage can be filled with word filler. However the only way to eliminate the infestation (which undoubtedly will exist in other areas of the building), is to expose all tunnels for treatment, replace timbers with properly treated wood, treat all furniture, pictures etc and introduce a monitoring and baiting system, to ensure ongoing termite ‘management’.

Guaranteed timber treatment:
The best method of timber treatment is via pressure impregnation, where the preservative is forced under pressure throughout the body of the wood in a special tank. As this is expensive and did not exist when many older properties were built, most woods are surface treated on site, such that regular re-treatment (e.g. biannual) is needed. Unfortunately it’s the beam ends and unexposed areas that join, pillars / walls etc, that termites and other insect pests like best, and these are the very areas that are sometimes missed in on site treatment. Unless you have purchased or treated the timber yourself (or at least witnessed the application), you can never be sure that it has done. Never purchase a property on the word of the vendor that evident insect infestation has been treated, unless they can produce a certificate and guarantee from an approved treatment specialist. Ultimately a full solution would include fumigation of the property in addition to pressure injected treatment of all timbers by a specialist.

NB:- Information for advice purposes only. Proper safety precautions should be taken  and legal procedures followed when carrying out all works.

Information provided by Mark Paddon BSc Hons Building Surveying. MCIOB. Structural Surveys throughout Valencia and Alicante . www.surveysspain.com  T: 962807247 M: 653733066 . Free 17 page  property buyer’s guide and advice available via e-mail request to This email address is being protected from spambots. You need JavaScript enabled to view it.

ã Mark Paddon 2008

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