Answers to decking questions

1 How do I remove a slippery surface that has formed on my deck?

It is advisable to use a mild detergent solution to clean lightly soiled boards. More intensive cleaning can be achieved by using a specialist decking cleaner or algaecide that will remove deeper stains, dirt and algae growth. These cleaning products are widely available from DIY stores.

2 What finishes can I apply to decking to give it a longer life?

There are a number of special decking stains that will protect a deck from wetting, sunlight and excessive wear caused by foot traffic. Stains can penetrate the surface layer of the timber to provide a deep layer of stained timber that sustain the colour as it wears away.

Wax emulsions can be applied to improve the life-span, other treatments such as teak oil will only give protection for short periods. Varnishes should not be used because they will turn yellow over time as they react with the sunlight and will eventually flake off.

3 What species of timber should I use to build a deck treated?

There are a variety of hardwood and softwood species that are considered suitable for timber decking. For softwoods, suitable species include: Redwood, Western Red Cedar and Southern Yellow Pine. Suitable hardwoods include: ipe, balau, iroko, European oak and jarrah. Softwood timbers will usually require preservation treatment before use, in order to give the timber an adequate level of protection from decay.

4 Can I use regular metal fixings on my deck?

It is advisable to use either galvanised or stainless steel fixings to avoid rust stains on the timber. Screws are preferable to nails, they should be used on decks that will carry higher volumes of traffic and make removing/replacing boards much easier.

5 What size gap should I leave between each deck board?

The gap between boards should be at least 4mm. This will allow efficient drainage of the deck and avoid droplets to becoming stored between the boards.

6 How should posts be installed into the ground?

When posts are installed directly into the ground, it is advisable to prevent any direct contact with the soil. The most common method is to sit the past on a concrete block or pad and backfill with concrete made without the use of sand.

Alternatively, a range of pre-fabricated post holders are available from builders merchants and decking stockists.

7 What joist span should I use?

The distance between the supporting sub-structure members varies according to the section size, wood species, strength grade and the amount of traffic expected on the deck. Span tables have been calculated for a variety of these combinations. It is important to take expert advice from specialist contractors or decking specialists.

8 How long will my deck last?

If a deck has been constructed correctly using suitable design details, it will last for many years; many companies guarantee the timber for 20 years or more. A periodic maintenance routine will usually be required in order to keep the structure in good condition. Such a routine may include cleaning away any surface dirt and re-application of a preservative treatment and/or stain/finish to provide protection from weathering.

9 Do I need planning permission for a deck?

Private domestic decks do not require planning approval providing they are not within 20 metres of a highway or exceed 3 metres above ground level.

If the deck provides the only access to the primary entrance of a building, Part M of the Building Regulations for England and Wales and Part T of the Technical Standards for Scotland should be satisfied.

Guard rails and balustrades should conform with Part K of the Building Regulations for England and Wales and Part S of the Technical Standards for Scotland.

If you are unsure about the planning requirements of your decking project consult with your local planning office who will examine your plans.

Most information courtesy of TRADA