Weathershield or Lumbersider on weatherboards: how they differ

Resene Lumbersider and Dulux Weathershield Low Sheen are both 100% acrylic, low sheen, waterborne exterior paints, and both manufacturers list timber and weatherboards as a use, so either will do the job on sound, properly prepared boards. The real differences are in how each maker wants bare timber primed, how many coats its system calls for, and what else the paint is approved for, and all of that is printed on the data sheets.

This is a comparison of what the two manufacturers publish, not a verdict. Neither data sheet proves one paint is better than the other, and anyone who tells you one is simply better is passing on a preference.

What do the two data sheets actually say?

The figures below come from Resene's Lumbersider data sheet (D34, May 2023), Dulux's Weathershield Low Sheen data sheet (NZDU00231, version 48, June 2026) and Dulux's current product page. Data sheets get revised, so check the current version at the shop before you buy.

What the maker states	Resene Lumbersider	Dulux Weathershield Low Sheen
Resin	100% acrylic	100% acrylic
Finish	Low sheen	Low sheen, gloss level 5 to 20 at 60 degrees
Where it can go	Exterior and interior	Exterior
Bare timber	Prime with the appropriate timber primer for best results	Self priming on most surfaces; three coats of Weathershield on bare unpainted timber
Usual number of coats	2; some colours need an extra coat	2 or 3
Theoretical coverage	12 square metres per litre	16 square metres per litre
Dry film per coat	33 microns	24 microns
Recoat time	2 hours	2 hours
Roofs and drinking water	Listed as suitable as a roof coating and for surfaces used to collect drinking water, with downpipes disconnected until the first shower of rain	The data sheet's limitations say do not apply to roofs or surfaces used for the collection of drinking water, although the same sheet also gives a Zincalume/galvanised iron roof system; check with Dulux before using it on a roof

Dulux also sells Weathershield in gloss, semi gloss and matt, according to its product page. That matters if you want the same product family on the boards and a different sheen on the trim.

Why does one need three coats on bare timber and the other two?

Because the two systems count coats differently. Resene's system for bare timber is a primer followed by two coats of Lumbersider. Dulux's system for bare unpainted timber is three coats of Weathershield, with no separate primer, because the paint is sold as self priming. On new bare boards both routes end up with three layers on the wall.

The coverage figures need the same care. Weathershield's theoretical coverage is higher per litre, and its dry film per coat is thinner, at 24 microns against Lumbersider's 33. Comparing litres per square metre without counting coats and film build will mislead you on cost. Both figures are also theoretical. Resene's own painter training notes say unpainted rough sawn timber uses 30 to 40% more paint than smooth board, so rough or weathered boards will not get anywhere near the number printed on the tin with either product.

Which one is meant for smooth weatherboards?

Both list weatherboards, but Resene's training notes for painters are telling about where Lumbersider sits in its own range. For rough sawn weatherboards Resene recommends Lumbersider because of the rough profile, and describes it as self priming in that context. For new dressed, smooth weatherboards, the Resene system in the same notes is a primer followed by two to three coats of Sonyx 101 semi-gloss or Hi-Glo gloss.

That does not make Lumbersider the wrong choice on smooth boards. It is a low sheen paint, and plenty of people want low sheen on a villa's weatherboards because it hides minor unevenness in old timber. It does mean that if you want Resene's first-choice system for new smooth boards, you would be looking at a different product. The trade-offs between sheens are covered in our guide to sheen levels.

On the Dulux side, the data sheet lists exterior timber including dressed and rough sawn timber for Weathershield Low Sheen, and the product page describes MaxiFlex technology intended to expand and contract with the surface.

Does either paint fix bad preparation?

No, and both data sheets say as much in their own way. Dulux's data sheet warns that apparently sound old paint can lose adhesion when it is recoated, particularly with a darker colour, and it describes a simple adhesion test: cut an X through the old paint with a sharp knife, press tape firmly over the cut and rip it off. If the old paint comes away on the tape, it should be removed before repainting.

Resene's Lumbersider data sheet says any timber exposed to the weather for more than one week needs thorough sanding or treatment with Resene TimberLock before painting. That applies to the weathered grey face of an old board just as much as to new timber left unpainted on site.

On an older Wellington villa or bungalow, preparation is also where the health risk sits. Health New Zealand advises presuming that homes built in the 1980s or earlier were painted with lead-based paint, so have it tested before sanding or stripping. Whether the boards need a primer at all depends on what is underneath, which is covered in when you actually need a primer.

Do temperature limits or guarantees separate them?

Temperature is one real difference. Lumbersider's data sheet says not to apply it below 10°C or when the temperature is likely to drop below 10°C during drying. The current Weathershield data sheet and product page both give 5°C as the minimum, during application and drying. Older Weathershield data sheets said 10°C, so if you are working from an old printout, check the current version.

Dulux's product page and current data sheet say that, for residential use, Weathershield is guaranteed not to peel, flake or blister for as long as you live in your home, with full conditions on the product label. The data sheet's separate non-residential warranty, of up to 25 years on request, is tied to application under an approved written Dulux DuSpec specification, with free paint for the affected areas as the remedy. Dulux notes on the product page that its guarantee sits alongside your rights under the Consumer Guarantees Act. Read the terms before you rely on it.

So which should go on your weatherboards?

For most houses the honest answer is whichever system you or your painter will follow properly. A few genuine deciding factors:

• Roof or rainwater tank on the same job. Lumbersider is listed for roofs and drinking-water catchment. The Weathershield data sheet rules out drinking-water catchment; on roofs it is contradictory, so ask Dulux before relying on it there.
• Bare new timber. Decide whether you want a separate primer plus two topcoats, or three coats of a self-priming paint, and budget the coats rather than the litres.
• Smooth boards and a cleanable finish. If you are using Resene, its own notes point smooth new boards toward Sonyx 101 or Hi-Glo rather than Lumbersider.
• Colour. If your colour was picked from one maker's chart, buying that maker's paint avoids a colour-match step.

Do not spend extra chasing a brand when the old paint is failing underneath. Money spent on scraping, sanding and priming does more for the life of the job than the name on the tin. For the wider brand question, see our Resene and Dulux comparison.

If you would like someone to look at your weatherboards and tell you which system suits them, get in touch for a free quote.