|
TERMITES
AND BORERS
The
nerve-racking part about buying a house is that more often than
not it is the unseen problems that cause all the heartaches.
Termites and borers are among the most feared.
They conjure up vivid pictures of teams of nasty little creatures
voraciously chomping up a house to a pile of rubble.
According to statistics from Archicentre, the
Royal Australian Institute of Architects Home Advisory Services
company, which has inspected tens of thousands of homes for Australian
home owners, after rising damp and cracking, termites and borers
scare people the most.
Part of this fear comes from the unknown. Most
people don't understand termites and borers, but like everything,
once the cause and remedy are explained, the problem doesn't seem
so bad.
TERMITES
(Also known as "White Ants")
If it is any comfort, although Australia
has its share of the horrid crawlies, they are nothing compared
with their cousins in tropical Africa who can reduce a house to
rubble in three months.
In northern Australia, they can grow up to 15mm
long (mastotermes darwiniensis) and will devour wood, cow
dung, paper and corn for their cellulose content. They are known
to attack lead-coated cables, make holes in plastic water pipes
and even attack billiard balls.
There are over 300 species of termite in Australia,
but only about 30 cause damage of any economic significance. Only
Tasmania is free of "economically significant" termite
attack to buildings. Other States' termites may be smaller than
the species in the north of Australia but can be more numerous
and just as voracious.
Termites are prevalent in moist sandy soils,
like beachside suburbs especially where underground water is present
(one in ten houses or more is likely to have had termite trouble)
but clay and other soils are also quite susceptible. In Melbourne,
there is a pattern of termite activity along the Yarra river basin.
But they can attack anywhere and no suburb is immune.
Termite behaviour
Termites are good at predicting weather
changes. Even before a heavy warm-season downpour begins, swarms
of the reproductive caste termites (alates) are released
from the nest and fly away to form new colonies. Fortunately,
of the millions that set out, only an occasional pair succeed
in finding a suitable site, and many of these are taken by predators
or die by desiccation. Warm humid weather conditions are favoured
for the short flights, which usually occur during the warmer months.
Once established and mature, the Queen termite
can produce up to 2000 eggs a day! This represents a huge potential
for ever increasing timber destruction, if conditions are right.
Main and often subsidiary nests are excavated
underground or in rotted tree stumps and woodpiles, wherever humidity
is high. Underground galleries are dug to search for wood. The
galleries preserve the moist atmosphere of the nest, shield the
termites from light and protect them from predators (largely ants).
Their network of galleries can stretch for a hundred metres from
the nest in search of food.
Where their galleries leave the ground (for example
to feed on a house's floor framing) the termites construct shelter
tubes with the same properties as galleries. They are usually
about 20mm wide and look like piled-up mud trails, being constructed
of soil and fecal material, bound together with termite saliva.
These mud shelter tubes are the best way of identifying termite
activity. The tubes may be seen climbing up the walls between
the ground and floorboards, or if your house has stumps, snaking
over ant caps between stump and bearer.
Once new food is found, the colony can virtually
excavate the whole of the inside of the timber, leaving only a
honeycomb of tunnel walls and a thin outer layer which preserves
the controlled atmosphere. The destruction can be devastating
and may be remarkably quick.
How to get rid of termites
The annoying part is that termites are
hard to find even for experts and it is usually only after a chair
leg goes through a weakened floor, or the vacuum cleaner head
crushes a hollowed-out skirting board, that people notice their
unwelcome visitors for the first time. Termites typically heave
the thinnest of harriers between themselves and the atmosphere:
sometimes the mere thickness of a coat of paint, which is a way
of identifying them.
They are normally first noticed in low density
woods like skirtings, architraves, floorboards and pine houseframing
timbers, but can extend into denser hardwood timbers if not eradicated.
Termites can be eradicated. This usually involves
puffing one or two grams of toxic dust into their galleries and
covering over the entry point after puffing. Termites clean or
"groom" each other and so pass on the toxic dust that
has adhered to their soft moist bodies.
They also cannibalise dead members of the colony
and eventually the toxin is passed through the entire colony.
An expert should perform the eradication treatment,
so make sure you contact only currently licensed members of your
State's pest control association. These people will also set up
a chemical barrier around the walls, foundations and footings,
to discourage the termites from returning.
Before commencement of the service, ask the expert
for a written statement describing the number and location of
the termite-damaged timbers. Also ask them to list any inaccessible
areas of the house possibly affected; details of treatment proposed;
any guarantees on the service provided and a list of timbers requiring
replacement or support.
 A
full statement may not be possible until after the termite treatment
has taken place (for fear of disturbing their active workings
and making treatment ineffective) but the expert should be prepared
to make out a statement soon after the treatment has had its effect.
Other experts such as the Archicentre Inspection
Service may be needed to assess the structural repair needed for
the house.
Maintenance items
To guard against termite attack, there are several precautions
that should be taken:
- Remove all timber debris from under the house,
since its presence encourages foraging termites. Move piles
of timber or firewood (potential food source for a new colony)
away from the house, and store the timber in a dry, well ventilated
location. Old decayed tree stumps should be removed to below
ground level. If you notice what you think is termite activity,
take some live specimens and have them identified immediately.
- Provide good ventilation under all suspended
floors. The reduced humidity and moisture makes the subfloor
area vastly less attractive to termites. Leaking water pipes
or bad drainage encourages termite presence so these faults
should be remedied.
- Never disturb what you think may be termite
activity. This prompts the termites to move elsewhere which
makes future detection and eradication more difficult. It may
also result in the damage being increased elsewhere.
- Examine new constructions: for example, verandahs
and timber decking, if built on stumps, may not have ant caps.
These constructions, and concrete additions to the house, may
also bridge previously laid chemical barriers, permitting unobserved
termite entry. The underside of a concrete slab is a popular
place for termite nests. If you have concrete laid next to the
timber frame of your house damp conditions may be promoted and
termite entry would be extremely difficult to detect. You should
consider this when renovating: if concrete-next-to-timber is
part of the design, have an expert lay a chemical barrier down
first.
Prevention is better than cure
If your neighbours have had termite problems,
or you suspect you are in a termite-prone area it may be wise
to obtain a pest inspection. The cost of such an inspection compares
favourably with the cost of eradication and replacement of affected
timbers.
Footnote- (Queensland only)
West Indian Drywood Termites
These destructive
termites were first recorded in Maryborough in 1964. They do not
need access to water or earth, so do not leave the normal termite
mud tunnels, thus are harder to find. Colonies have since been
found in Maryborough, Bundaberg, Childers and Brisbane.
They have been declared a "notifiable disease"
and eradication treatment is performed without cost to the
householder. You can minimise the chance of infestation
by thoroughly examining second-hand timber and furniture before
introducing it to your house. West Indian termites leave very
small oval shaped pellets, brown, black or reddish in colour,
near the site of attack.
If you suspect you have them, send samples of
the pellets (or "frass") to the Queensland Department
of Forestry. The Department urges the public to be vigilant and
hopes to eradicate this pest completely.
BORERS
There are several
types of timber borers in Australia, some serious and some not,
so it is important to identify them if you think you have a problem.
Borers are actually all different families of
beetles. Some of the relatively harmless ones not needing any
special eradicative treatment are pinhole borers, longicorn borers
and auger beetles.
Pinhole borers cannot survive in timber once
it has dried out, so they normally leave before, or soon after,
the timber is used for construction. You can identify them by
examining their "flight holes" (the holes made when
leaving the timber). These holes will rarely have borer dust (or
frass) around them, since in most cases the insect is long gone
or dead. They leave relatively few holes unlike the more destructive
species shortly to be mentioned.
Longicorns leave oval-shaped holes 6-10mm in
size as they emerge from framing timbers or wall linings. They
are not a serious structural problem because, unlike the more
destructive species, they cannot breed in the timber and therefore
cannot proliferate. The size and shape of their flight holes makes
this borer easy to identify.
Auger beetles, again fairly harmless, are harder
to distinguish from the more destructive Iyctid borers mentioned
below. One way of telling them apart is that auger beetles leave
far fewer flight holes since they cannot proliferate in the timbers,
so are far fewer in number. However, differentiating them from
Iyctids is not normally important, since if conditions are right
for auger beetles, they are even better for Iyctid borers, so
if one species is present, you will normally find the other.
Lyctid borers
Lyctids are very common in Australia
and attack the sapwood of certain hardwood trees. Sapwood is the
living band of wood around the outside of the tree. Each State
has its own regulations limiting the amount of sapwood to be cut
from felled trees, some States try to eliminate its use altogether,
or require susceptible sapwood to be treated.
In the southern States, Iyctid attack to the
sapwood of framing timbers is common. But the amount of sapwood
in a framing timber is usually small, so borer attack will not
seriously affect the timber's strength. And being out of sight,
the borers will rarely be noticed. However, within three to five
years of the house being built, Iyctids could be found in skirting
boards and architraves and these are highly noticeable timbers.
Because timbers like skirting boards are thin,
they could in some cases be cut almost exclusively from the outside
of the tree and be largely made of sapwood, food for Iyctids.
So these timbers could be riddled with Iyctids.
Lyctids can be recognised by their 2mm holes
and large quantities of flour-like dust. Although not a problem
structurally, they are certainly unsightly and have probably put
the wind up more homeowners than any other single cause. If Iyctid
attack is visible, you could replace the affected timbers. Otherwise,
they do not need any special treatment.
Anobiid borers
Anobiid borers are more serious and attack
softwoods, especially varieties of pine (although very rarely
do they attack the common Pinus radiata). Like Iyctids, anobiids
are widespread throughout Australia. The Anobium punctatum
species especially loves Baltic pine, commonly used 40 to
140 years ago but still occasionally used for floorboards and
weatherboards. The "Queensland pine" anobiid Calymmaderus
incisus located from northern NSW and farther north has a
similar love for Hoop pine.
Anobiids tend to channel along the grain of the
wood, making the odd 2mm pinhole and leaving large quantities
of loose gritty dust with a texture of fine table salt.
They are capable of eating for years and will
happily chomp away anonymously under the carpet. Be suspicious
if your floorboards get spongy as this is a common area for them
to attack.
You will probably first notice the floor feeling
spongy at one end of a large room (like the living room) because
a big floor area will deflect more noticeably.
Also be aware that second hand or antique furniture,
or old floorboards may contain borers, so examine such articles
well before introducing them into the house.
Anobiid damage must always be attended to. Homeowners
have sometimes stopped infestation by removing all significant
borer-infested timbers and replacing them with non-susceptible
timbers, then monitoring the results. Such treatment is only worthwhile
if sub-floor humidity is simultaneously reduced, because borers
thrive in damp conditions. Humidity can be reduced by removal
of debris, increasing sub-floor ventilation (cleaning out vents
and possibly adding more) and draining damp soil where necessary.
In some cases Anobiid-infested timbers need chemical
treatment. As with termite eradication, it is recommended that
only currently licensed members of your State's pest control association
be contracted and that they should provide a written description
of proposed treatment as previously outlined.
One of the worst cases seen by Archicentre's
Inspection Service was in a house in Bentleigh, Victoria, where
the architraves, skirtings, doors, windows and cupboards were
all infested with termites. The house had been superficially renovated
to cover up tens of thousands of dollars damage.
Remember that the best way of avoiding expensive
problems is to be aware of them before you purchase your house.
Archicentre has carried out thousands of home inspections for
homeowners and prospective buyers to help them make a realistic
appraisal of the property before buying, repairing, or renovating.
BOOK
AN ARCHICENTRE INSPECTION
|
