What we deal with
Thatch jobs in the Western Cape tend to fall into a few patterns. The most serious is borer in the structural poles and laths, where powder post beetles go for the sapwood of hardwood poles and other wood borers can attack softwood battens. The thatch layer itself shelters cockroaches, spiders, crickets and fishmoths, which then drop into the rooms below. Rats and mice tunnel through the thatch and nest against the ridge, and birds pull out the reed to build nests, bringing bird mites with them. We also treat lapas, braai areas and game farm chalets in the Boland where the thatch is open underneath and easy to inspect.
Signs to look for
Tick every sign you have noticed. It takes ten seconds.
Why it matters: Borer in the poles and laths weakens the timbers that carry the weight of the thatch, which is heavy, and serious damage can mean replacing structural members. Rodents nesting in thatch chew electrical cables, and in a thatch roof that is a fire risk to take seriously. Insects dropping from an open thatch ceiling are a nuisance in homes and a real problem in guest lodges and restaurants. Bird nests in thatch can bring mites into bedrooms below.
How we treat it
We start by inspecting the underside of the roof, the poles, the laths and the eaves, looking for borer exit holes, frass and rodent or bird activity. Affected poles and laths are treated with a borer spray or injection designed for timber, applied to the wood rather than soaked through the thatch. For insects living in the thatch, we use a targeted residual treatment on the underside, keeping it as light as will do the job. Rodents are handled with traps and tamper-resistant bait stations placed at wall plates and entry points, and we advise on bird netting or proofing at the eaves. Fire safety of the thatch itself, such as retardant treatment, is a separate specialist job and we will tell you if it looks overdue.
- Roof inspection
We look at the underside of the thatch, every accessible pole and lath, and the eaves and ridge.
- Identify the problem
We separate active borer from old damage and confirm which insects, rodents or birds are involved.
- Timber treatment
Affected poles and laths are treated with borer spray or injection.
- Thatch and pest treatment
Insects in the thatch are treated from below and rodent stations or traps are placed.
- Report and recommendations
You get a report noting what was treated and any timber that a thatcher or builder should replace.
Things most people don't know
Borer damage in thatch is often blamed on the reed, but the reed is rarely the problem. It is the poles and laths holding it up that the beetles are after.
Pale, fresh powder means activity; dark, compacted dust in old holes usually means the beetles left long ago. That distinction saves a lot of unnecessary treatment.
A technician looking at a thatch roof checks the wall plates first. That is where rodents get in and where they nest, warm and dry, against the top of the wall.
When it peaks in Cape Town
Adult borer beetles emerge mainly in the warmer months, so fresh powder and holes often appear from late spring into summer. Rodents move into thatch most during the wet Cape winters when it offers dry shelter. Treatment can be done at any time of year, though a dry day makes inspecting the roof easier.
DIY or call a professional?
Spraying the underside of your own thatch with a garden insecticide does very little for borer, which lives inside the poles, and soaking thatch in products not meant for it can do more harm than good. We would leave borer and rodent work in thatch to someone who does it regularly. Keeping the roof clear of overhanging trees is the one thing every owner can do themselves.
What affects the price
The price depends on the size of the roof, how much of the structure is exposed and how many poles and laths show borer activity. A small lapa with an open underside is a very different job from a double-storey home with a closed ceiling. Rodent and bird work is added where needed, and timber that is too damaged to treat has to be replaced by a builder or thatcher.
Preventing it coming back
- Ask your thatcher to check the poles and laths for borer whenever the roof is being repaired or re-combed.
- Keep trees and creepers trimmed back from the thatch so rodents cannot step straight onto the roof.
- Fit bird netting or wire at the eaves if birds keep pulling reed or nesting there.
- Have electrical wiring in the roof inspected regularly, especially if you have had rodents.
- Do not store firewood or boxes against the walls under the thatch, as they give insects and rodents cover.
- Have open thatch ceilings in lapas and lodges checked once a year, since problems are easy to see early.
Frequently asked questions
Do you treat the thatch for fire?
No, fire retardant treatment is a specialist job for thatching contractors. We treat the pests in the roof and will point out if the thatch looks like it needs attention.
How do I know if the borer is still active?
Fresh, pale powder below the poles and clean-edged holes point to active borer. We can tell you on inspection, or send us a photo on WhatsApp first.
Will the treatment damage my thatch?
No. We treat the timbers directly and keep any treatment of the thatch itself light and targeted.
Can you treat a lapa or braai area?
Yes, lapas are often the easiest to treat because the whole structure is open underneath.
Do I need to move out?
Usually not. We will tell you which rooms to keep clear during treatment and for how long.
Is there a guarantee?
Our treatments carry a minimum 3-month guarantee, and the report records exactly what was treated.
Thatch Treatment by area
We cover all of these suburbs from our base in Brackenfell. Pick yours for local advice.
