Bridging a Gap in Current Thinking

The Case for Introducing Preservation and Pest Control Measures In Buildings From The Outset

It’s not a thought often considered by those working in the architectural and construction professions, but they can play a key role in keeping buildings free of damp, insect infestation and pests – with measures introduced on the drawing board and out on the building site for maximum effect.

Supported by a programme of maintenance after the handover stage, the end result is a comfortable, healthy environment for the long term.

In this article, trade bodies The Property Care Association (PCA) and The British Pest Control Association (BPCA) have joined forces to highlight ways to preserve and protect properties in the UK – and help keep out any unwanted guests.

Hidden Issues in Sustainable Construction

Modular, off-site building methods are being warmly welcomed by many in the construction sector, who recognise the sustainability benefits and fast-track nature of the process.

However, one area which should be carefully considered by specifers are the pallets and packaging the modular products are transported in, from exporting countries.

Species including the Pine Wood Nematode (a microscopic worm like pest spread by a wood boring beetle known as the sawyer beetle) and the Asian Longhorn Beetle can be transported into the UK via this route – and ultimately they can impact severely on the UK countryside and urban areas.

Both of these pests can prove detrimental to our forests and urban street trees and, if significant numbers take hold, wooded areas and avenues of trees would need to be felled to control their spread.

It is an EU requirement that all wooden packaging and pallets imported to members states from third countries (or from Portugal, which has an outbreak of Pine Wood Nematode) have been treated by an ISPM 15 approved measure, so that this risk is removed.

According to the BPCA, peace of mind is assured by ensuring wood pallets and packaging are treated and marked to the International Standards For Phytosanitary Measures No 15, (ISPM 15)

David Hammond, managing director of Thermokil Ltd, runs the BPCA’s courses on heat treatment for insect control. He said: “Packaging and pallets can be produced from inferior wood, including deadwood, which is more likely to be infested, as it may have been allowed to stand around for a period of time.”

Anyone with concerns in this matter should contact the BPCA, or the Forestry Commission, for advice and guidance on the subject.

Tackling the Condensation Season

As well as the use of greener materials in construction, the quest for a more sustainable building industry – and a long term reduction in energy bills – means more efficient homes and properties.

However, these greener properties can harbour an emerging problem that construction managers and project managers might in the future need to help address – namely the issue of poor ventilation causing mould, damp and condensation.

This is a timely concern – as the beginning of winter usually heralds the start of the condensation season.

Day-to-Day Activities

Atmospheric moisture is created by occupation including respiration, washing and bathing, keeping pets, doing the laundry – both washing and drying – and cooking.

Steve Hodgson, general manager of the PCA, said: “With all these activities representing normal day-to-day activities, the creation of atmospheric water is natural and must be expected.

“When a building leaks air, the damp air within the building can move out and is diluted with air moving into the building from outside to replace it. This dilution of the damp air within a building reduces the relative humidity levels within the occupied space and decreases the likelihood of dampness, condensation and mould growth.

“To meet the needs for more energy efficient homes, when doors and windows and loft hatches are draught-proofed, walls are insulated, floors are covered in laminates and flues sealed, the rate of natural air exchange is dramatically reduced.”

Double Trouble

Simon Forrester, BPCA chief executive, says such conditions are not just ripe for cultivating damp and mould.

“From a pest control point of view, an elevated moisture content level within a building, particularly kitchens and bathrooms provides a good climate for pests.

“This can include psocids and book lice, as well as roaches – especially the German cockroach, which thrives in this type of environment,” said Simon.

“Moisture is absolutely essential to the growth and development of many public health insects. By reducing this through effective ventilation, air management, good design and effective building maintenance, the chance of such pest infestation is considerately reduced. Furthermore, reduced relative humidity also helps reduce the incidence of house mites, which in turn will help asthma sufferers.”

Addressing The Problem

Steve Hodgson believes that, in the future, there will have to be a balance between the economic reality of powered and passive ventilation, with the need to conserve heat and fuel.

Managing the characteristics of new build and refurbished homes that are better insulated and increasingly air tight with the expectations of the occupiers will also need to be addressed.

Steve said: “Solutions are available, but one size does not fit all. For construction and project managers the installation of vapour check layers within the fabric of the building are ideas for consideration, but the whole subject needs to be researched and considered overall.”

On-Site Action

Construction managers can also, at the earliest stage of a building project, take steps to minimise pest problems for the longer term.

While much thought is given to community and environmental aspects on building sites, the BPCA urges contractors to think about another perspective – pest infestations.

Simon Forrester said: “One of the biggest issues on a construction site is the opportunities packaging and materials present for harbourage.

“Rats burrow and make their nests, and when the builders move out the rats don’t move too – they’ll look to the new residents as a continuing source to survive from.

“We’ve had reports of rats infesting entire new developments, which does not leave a great impression for the new occupants.”

Action At The Design Stage

Richard Moseley is the technical manager of the BPCA. He believes that ideally at the design stage, architects, house builders and design and build contractors would consider consulting a BPCA member, as they can give advice on any problems likely to be encountered early on, following an investigation of the site, and make recommendations.

Richard said: “One of the major areas of our work is to prevent birds entering a building. We can advise on suitable action at the building design stage on works such as the proofing-off of nesting sites using netting

“It’s much easier to put these measures in place at the design stage, knowing the scaffolding is in place and the work can be carried out under the control of the main contractor.

“Another area of significance in the design stage is taking action on the spread of mosquitoes. We are seeing mosquitoes laying their larvae in standing water in the UK and the ground conditions on a building site can present a great opportunity for this activity.

“The warmer, damper seasons seem to be leading to an increase in the mosquito population.

“Traditionally we have approximately three dozen varieties in the UK. It appears however, that varieties such as the Tiger Mosquito are moving into Western Europe. As these mosquitoes are vectors for disease, anything that can be done to control their spread is important.”

According to the BPCA, other factors to consider at the design stage include placing a fine mesh over air bricks to prevent pests and rodents entering a building, and addressing the issue of voids where a ducted heating system is specified, for example in a multi-occupancy development, as these areas can provide a route for rats and mice to get into the entire structure.

Careful attention should also be paid to gaps in skirting boards in properties such as hotels, as bed bugs thrive by slumbering in these areas, and then crawling across to beds to target people sleeping, for their food source.

Finally drains and sewers should be specifed with hinged plates, not only to help address any potential flooding issues, but to stop rats progressing into properties via this route. Rats can even enter a property through a toilet if this is not properly maintained.

Richard added: “Public health issues are not generally considered by constructors and designers as being within their remit, but there is such a lot they can do to control and manage pest problems. It adds such a lot to a property when they do.”

Maintenance Matters

After the design and construction phase, both trade bodies see building maintenance as a critical factor in halting problems, not only in residential environments but commercial, retail and industrial areas too.
This year, the PCA appealed to property owners to call in the experts after unearthing evidence that badly installed cavity wall insulation can have a damaging effect on buildings.

The move came after the PCA saw a significant increase in the number of complaints from the public, who have find that dampness and decay can cause potential structural damage to their properties.

Steve Hodgson said: “We have had an increasing number of complaints about timber decay and dampness in homes following the installation of cavity wall insulation.

“We compiled a checklist of faults for the public and property managers to look out for as part of their maintenance programme, and we urge people to be vigilant as ultimately the issue can cause the corrosion of wall ties.”

The BPCA has also reported a significant increase in 2011 of a perennial problem – wasps. This year was a bumper year for the stinging pests – with figures showing it to be the worst on record for around 10 years.

Again, maintenance can help address the issue, with particular attention paid to sealing gaps between soffits and walls offering an effective method of preventing wasps nests being built in roof spaces, a major source of habitat for the pests this summer.

Flash Points

Both trade bodies report flash point areas, where property problems and pests can thrive if maintenance actions are not taken.

This includes drains, which should remain clear of leaves and other debris to enable water to escape from a building quickly, particularly during heavy downpours.

Such activity will help prevent water taking an alternative route, potentially into the internal area of a property, which can eventually lead to damp problems.

From a pest control point of view, as described above, hinged plates on drains and high risers can also help stop rats entering a building.

Roofs should also have their lead-work and roof tiling checked, as any loose or worn areas can soon become exposed, allowing water to find its way in, as well as wasps and masonry bees.

Finally, gutters should be free from moss, leaves and other debris – and all properly connected up – to give water a fast exit from the building and prevent the entry of pests.

Take The Right Advice

As long-established UK trade bodies, the BPCA and PCA (formerly the BWPDA) have both built-up a wealth of experience in their relevant sectors.

With regular training programmes, expert technical panels and carefully selected members, both associations can offer property professionals peace of mind in the service they will receive.

More about the BPCA and its expertise in pest control can be found at www.bpca.org.uk or by calling 01332 294288.

The Property Care Association – which represents the damp control, timber infestation, flood recovery, basement waterproofing, structural repair and condensation industries – can be found online at www.property-care.org or contacted on 0844 375 4301.