Pine Decking

Pine Decking

We stock 22x105mm and 32x105mm Smooth Pine decking


South African Pine decking is an excellent exterior decking. If installed and screwed correctly, there is little reason that pine decking should not last for many years. It is our top selling decking product !

Printable page for onsite use: Somerset Timbers Decking Installation with Screws

We treat our pine decking to with CCA to H3 exterior specifications ensuring guaranteed protection against timber rot and termite attack.
Our decking is manufactured from dried and selected Southern Cape radiata pine. This is the best quality pine available and is vastly superior to pine species from the northern area of South Africa.

We manufacture Pine Decking in 22x105mm and 32x105mm size with a 4mm radius rounded edge on each corner.
We stock the following lengths: 1.8m, 2.1m, 2.4m, 2.7m, 3.0m, 3.6m, 4.2m, and 4.8m (other lengths are available on special order)


The recommended span for 22mm pine decking is 450mm.
The recommended span for 32mm pine decking is 600mm.
It is critical that the supporting structure is correctly designed. A poor quality deck is often the result of a poorly or under designed supporting structure.


We supply specialised stainless steel Decking screws.

Use 2 screws at each joist. Our 22mm decking requires a 50mm length screw and our 32mm decking requires a 70mm length screw.
At the recommended 4mm spacing you require 40 screws per square metre.

We do not recommend using standard Passivated posidrive screws – they eventually will rust.
The use of EasyClips is not recommended – pine is not hard enough to take a biscuit join on edge.
Placing boards against each other is NOT recommended as no ventilation is allowed.

A comment on stress grooves: Our experience has shown that stress grooves on pine decking cause problems such as cupping and splitting and prefer not to add them to our decking.


After installation, Somerset Timbers Galseal should be applied to feed oil back into the timber. Various colours are available.
This can be reapplied as necessary – a 2nd coat probably after 6 months and then yearly. Alternatively Boiled linseed oil thinned with turpentine can also be used.
The use of surface sealers and varnishes is not recommended as this causes the timber to heat up excessively in hot conditions and does not allow the timber to breathe.

General notes

Longevity: The first question we are asked: “How long will pine decking last ?” We have good experience that if a pine deck is properly maintained from the beginning it can last indefinitely.

Poor deck performance ? These are the top 5 problems we encounter:

1. Insufficient oiling of the deck: This will result in the timber fading and showing drying cracks. The use of varnishes and heavy sealers is NOT recommended. These products prevent the timber from releasing rain water and eventually cause cracking and over drying of the timber. Remember that the CCA treatment of pine does NOT protect against drying out, cracking or UV degradation. This is a common misconception. Timber decking needs to be protected from the elements by feeding oil back into the timber at regular periods depending on exposure.

2. Poor quality fasteners: Cheap steel Posi drive screws may save money initially but eventually are prone to rusting and breakage. Stainless steel screws are the recommended option.

3. Incorrect spacing of supports: It is vital that the sub structure is spaced according to the decking used. Deck boards which sag between joists are a definite indication that the joists were spaced too far apart.

4. Insufficient and incorrect fasteners: The rule is: 2 screws at every joist. Using only 1 screw per joist may save you 2% of the cost of your deck but is sure to cause problems such as loose boards, cupping (resulting in no water run off), warp and twist. Decking stands out in the sun and rain every day and is under severe stress. It is vital that the correct number and length of screws are used.

5. Poor workmanship: Shortcuts, inexperience and a combination of the above are sure to result in problems. Ensure you use reputable builders or if doing it yourself please ask us for advice !