Timber decks are marvellously flexible structures that can be designed and built
to suit you, your family and the property you live in. They make great additions
to homes of all ages and are superb for businesses like pubs, clubs, hotels and
restaurants that want to create an attractive outdoor room for their customers
The TDA was set up to provide help and advice about decking and set out here
are the answers to the questions which are asked most frequently.
If your query isn't covered then please complete the enquiry form at the end
of this section and the TDA help desk will get back to you.
The coating on my deck boards is flaking off?
The key thing about colouring deck boards is that the
coating that you use is suitable for the purpose. Products that are
intended for use on vertical surfaces like cladding, doors and windows
have properties that do not lend themselves to flat surfaces that are
subject to footfall and particularly the movement of timber as it
responds to changes in moisture content throughout the season. This is
the primary cause of peeling and lifting.
The type of product you need is one designed specifically for decks in
that they penetrate rather than coat the surface and are resistant to
scuffing by footfall.
Cuprinol make a great range and all of their products carry the TDA
“DeckMark” quality marque. If you check out their page on our website
you will find their range of stains & oils listed.
Does treated timber vary in colour from one piece to another?
Freshly treated timber will have variations in colour between one piece and another. This is due to the relative proportions of heartwood and sapwood in each piece. Sapwood is more permeable than heartwood and so takes up more preservative which results in an initial variation of colour from green (sapwood) to beige (heartwood). Once installed and exposed to the elements, the initial strength of colour fades to a warm, honey brown and in the long term will become a natural silver grey all over.
Remember, timber is a natural product and variations in character are to be expected. Occasionally timber containing high or mobile resin levels can give a blue colouration at the time of treatment. However this fades rapidly into the overall natural green/beige colour.
Do decks need planning permission?
Timber decks differ from conventional patios and terraces most significantly in their elevation and general height of construction.
For all but the simplest, low-level garden deck, property owners should satisfy themselves that planning regulations do not apply to their proposed structure.
In addition to contacting the Local Authority, we strongly recommend that you talk to all your neighbours about your plans. Neighbour objections are the most usual reason for planning refusal or enforcement notices after completion. Local Authorities can insist that structures are dismantled and removed where consent should have been obtained, but was not.
To see the situations where planning approval is required click here
What's the difference between hardwood and softwood?
Hardwood and softwood are broad biological terms used to describe species of wood. The terms have nothing to do with the physical hardness of the wood. Hardwoods come from broadleaved trees and softwood species from coniferous, evergreen trees.
There is a wide range of species of wood within each category that are highly suitable for decking. The important factor for wood used out of doors is that it is durable enough to resist fungal decay. This means using a hardwood classified as naturally durable (some are not) or a softwood given extended durability through pressure treatment.
Over 90% of all decks are made from suitable pressure treated softwoods because of their availability, ease of working and cost effectiveness. Hardwoods come in a range of attractive colours. They tend to be more expensive and require more care to work with than softwoods.
Always use timber from sustainable forest sources.
For more details about suitable timbers for decking click here.
How long will a timber deck last?
A timber deck should provide years and years of pleasure. That's because naturally durable timber species or rot proof pressure-preserved wood is used in their construction. If the deck has been built using the correct materials and good building practices then it will last almost indefinitely if properly looked after. In fact, timber that conforms to the TDA DeckMarkTM Quality Scheme will come with a performance warranty of between 15 and 25 years.
Are decks slippery in wet weather?
The key factor in preventing slipperiness is to ensure that the deck surface is kept clean and surface deposits such as mildew, algae and fine mosses are kept at bay for it is these deposits that cause slipperiness on any surface, even stone flags, in wet weather.
Our recommendation is to give decked surfaces a frequent brush with a stiff broom and to give them a thorough clean once a year in spring or autumn using either a power spray washer or a proprietary deck cleaning product.
TDA members produce a range of deck cleaning, maintenance and decorative products to help keep decks looking good.
Do decks attract rats?
Of all the possible places for rats to set up home, underneath a properly installed deck is one of the most inhospitable of places. This is because a sterile area is created before construction using a weed-suppressing sheet held in place with a layer of gravel. Because a gap is left between deckboards to help drain the surface dripping rainwater does not make for a dry, secure home. A small pea, let alone sufficient food to feed a single rat, could not find its way through this gap.
As with the underside of garden sheds, precautions should also be taken to prevent leaves and other windblown litter accumulating by using boards or close-mesh wire netting. If you compost your waste food then it is best to use an enclosed/covered composter rather than an open heap which do tend to attract vermin.
The TDA exists to set standards for the materials and practices used in deck construction. You should have no qualms whatsoever about rats moving in if the TDA guidelines on deck construction and aftercare are followed.
For guidance on how to avoid rats being attracted to your garden
Will grooved deckboards perform better than plain ones in preventing slipperiness?
By far the majority of timber decks, boardwalks and piers built around the world are surfaced with plain timber boards. Whilst grooved deck boards are often marketed as "anti-slip" there is no evidence to suggest that they perform any better or worse than plain decking. Choice of deck board style is therefore a matter of personal preference.
A fall of around 1:100 should be built into a deck to help the surface drain and prevent standing water. Grooved deck boards were actually designed to aid water drainage and as such should be laid in the direction of the fall away from any adjoining property.
Where there is a higher than normal requirement to prevent the risk of slipperiness, for example on ramps, stairs, bridges or on public/commercial installations then deck boards with built-in abrasive strips can be used.
The TDA should be contacted for details of DeckMarkTM quality assessed manufacturers of such boards.
What fixings do you recommend?
Fixings used out of doors should be corrosion resistant to prevent rusting and weakness of the structure in subsequent years.
Nails can be used for fixing - but screws are ideal. Screw size should be three times the thickness of boards and they should be positioned not closer than 25mm to edges and countersunk below the surface. Fixing points at the ends of boards should be pre-drilled to prevent splitting. All screw points in hardwood deck boards should be pre-drilled 2mm oversize and countersunk before fixing.
The advantage of screws over nails is that they are more secure than nails and enable boards to be lifted easily to gain access below the deck for maintenance or repair or fixing lights and can be re-tightened if necessary.
Bolts, joist hangers and concealed deck clips should also be made of similar rust resistant metal.
Can decks be installed above the damp proof course (dpc) of my home level with a door?
The dpc exists to prevent dampness rising into a dwelling and should never be compromised or bridged. This is why one often sees advice to install decks well below dpc level particularly where the deck is a DIY project.
However, decks can be installed level with doors or patio windows using the following technique:-
- A ledger board (joist) is fitted to the wall using exterior grade bolts with galvanised or plastic washers around the shank to create a minimum gap of 10mm to allow water to run freely down the wall.
- It is important to keep this gap clear of leaves and dirt etc which might bridge the dpc.
- The deck support joists are then fixed to the ledger board using joist hangers. The joist framework should have a fall of 1:100 away from the property and have good ventilation underneath.
- Deck boards should be fitted at right angles to the ledger and with a 6mm gap between each board.
When should decks have a balustrade?
Balustrades (or parapets) on decks can serve several functions, ranging from simple decorative boundaries to full safety barriers. Even a small change of level can be a hazard, particularly for elderly or infirm users.
Unless the deck surface is flush with the surrounding ground level, a parapet or edge protection detail should be incorporated. For very low-level structures, this may take the form of a simple decorative rail, a trellis panel, a raised planter box, a bench or seat, etc.
The height of the parapet depends on how far the deck surface is off the ground:
For 'low-level' decks up to 600mm from ground level - parapet height should be 900mm
For 'high-level' decks over 600mm high - parapet height should be 1100mm
Where parapets act as safety barriers, they should be designed and constructed to meet the UK building regulations (the Building Regulations for England and Wales and the Technical Standards for Scotland).
The TDA has a Technical Bulletin dealing with deck parapet design and construction (Publication No. TBO4) and this is available for £5.
How do I keep my deck looking good?
All decks will benefit from regular brushing with a good stiff broom on a frequent basis throughout the year. Once a year, in Spring or Autumn, we recommend giving your deck a more thorough cleaning using a pressure spray or a purpose made product like Cuprinol Decking Cleaner which is formulated to remove grease and discolouration and restore the look of the wood. Keeping the deck surface clean in this way not only keeps it looking like new it also reduces the conditions that cause any surface to be slippery when wet.
Unless a deck is painted with a stain, the original colour of the timber used will fade gradually when exposed to the elements. Whether your deck is made from a deeply coloured hardwood or the more mellow hues of a softwood species it will fade over time to a pleasant grey . However, using a clear water repellent coating will help to prevent fading.
Timber is a natural product and as your deck timbers weather, small cracks are likely to appear on the surface of the boards. These are caused by the intermittent wetting and drying of the wood and are part of the character of wood. They have no structural effect whatsoever. This natural ageing process can be slowed by the annual use of a clear water repellent coating.
Resin is coming out of the timber?
Some types of timber contain a resin that may exude from the surface of the timber in hot weather and create rings of crusty white powder around knots in the timber. This resin is not at all harmful and can be removed from the surface of the timber with a stiff brush. It is unlikely that resin will continue to exude after the deck has been through its first summer.
Are the treatments used in protecting softwood decking timber in any way harmful?
No. Timber decking is entirely safe - even for pets and plants. The strictly controlled process of impregnating the timber means that the preservative substances found in decking are 'locked' into the wood - even when in contact with water.
Can I personalise my deck?
Yes - timber decks can be customised to your own style and decorative taste. The choice of additional design features - balustrades, pergolas, trellises, steps and so on - is almost infinite. The nice thing about timber decking is that it can be extended, or another level or a feature can be added in the future to enhance your enjoyment.
Will a deck support a hot tub or a summerhouse?
Yes, a deck can be designed to support almost anything you want to put on it. Hot tubs have become very popular but when full weigh several tonnes. It is vital that the decking structure is purpose designed by a structural engineer and appropriate stress graded timber used. For decks that are intended to carry loads like this we recommend contacting a specialist TDA company. For details see the where to buy
section on this web site.
How much should I expect to pay for a deck?
The price of a timber deck will obviously vary enormously depending on design and size and so on. However, it would be reasonable to say that a DIY-installed deck will cost a lot less than a professionally designed and installed one.
A professionally designed and installed deck will necessarily cost more - but compared to other major home improvements, such as a new kitchen or conservatory, decks are great value. Professional deck designers and installers who are members of the TDA have the knowledge and experience to ensure that you end up with a quality product that will last a long time and perform marvellously.
Can I install my own timber deck, or do I need professional help?
Several of the TDA member companies are professional deck designers and installers. Using one of them will give you the peace of mind that your deck has been designed and installed to the highest industry standards. Using a decking professional will give you access to the wealth of designs possible and top advice on finishes and maintenance procedures. Of course it is possible for the DIY-er to tackle decking, although a fair degree of competence is required.
Will I be hurting the environment if I use timber?
Not at all! The sort of wood used in timber decking comes from responsible producers who insist on proper management of their resources. This involves the conservation of forests through the use of sustainable forest management techniques and renewal through re-planting schemes. Timber is the only mainstream construction material that originates from a renewable resource and, as a result of the policies mentioned above the amount of productive forest in Europe (from where most decking timber comes) is increasing every year.
What is the DeckMarkTM scheme?
DeckMarkTM is a quality assurance scheme which is operated for the TDA by an independent company specialising in quality assessments. Seeing the DeckMarkTM symbol on a product or service is visual evidence that the company operates to standards set by the TDA.
Are there any publications about decking?
The TDA publishes a Manual for professional designers and installers which covers everything to do with deck construction including species selection, span tables and strength classifications.
The Manual sets the standard for best practice deck design and installation. To request an order form click here
Some of the TDA's own members publish guides, CD's or videos about deck construction. Contact BSW, Richard Burbidge, Arbordeck, Hoppings or the TDA office for details.