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Installation Tips for a Composite Deck

So you have researched all of the benefits of composite decking, decided that you don’t want to worry about water damage and the regular maintenance required with timber. The vast array of colours has been assessed and you have unloaded all the materials which are now sitting tidily on the corner of your drive, awaiting the magical transformation into a perfectly level solid deck. So where do you start with putting the whole thing together?


Always read the instructions

There can be some subtle differences in the materials and construction depending on where your composite decking boards have been made, and who by. It is therefore really important to check the manufacturer’s instructions that come with the decking materials.

One thing to be aware of when planning and designing your deck is the effect that thermal expansion of composite boards will have on the overall plan. The variation of temperature, humidity and rainfall in most climates is enough to affect the spacing of the decking between summer and winter. The expansion of composite boards mainly happens across their length so this fluctuation should be taken into consideration to avoid any buckling.


Choose your screws wisely

The installation is one of the most common times to cause damage to your deck. If a standard ‘bugle head’ screw is used, when it is tightened it can pull a small amount of composite material above the surface. This is known as mushrooming and can be prevented by using reverse thread screws. The resulting bumps can be levelled with a hammer but it is something that’s best to be avoided when possible. Hidden fasteners are available for some composite decking materials. These fit securely into a cavity that runs down the side of the decking boards after being screwed into the side of the frame.

If you are using a hollow composite decking board, the ends will reveal the cavity that runs through the length of the deck. This is a sure way to ruin the clean lines of your new installation. You can hide these holes by using matching end caps that can be attached, covering the holes. An alternative is to install a picture frame or racetrack pattern perimeter which will also cover the open ends.

Make sure the frame is strong

When you are building the frame it is a good idea to construct blocking around the perimeter to add extra rigidity. Double joists should also be inserted to further support the seams. The double joists have to be perfectly level with each other, the decking will not sit flat if this is overlooked. Check with a spirit level and fasten with 4 screws and 12inch distances to keep them solid. When fastening hidden fastenings over the double joist, if you can lay the sequential boards so they join over the double joist you can use 2 fittings which will help keep the decking securely fastened to the base.

Where to start?

The sequence of installation should start at the house end, or the end which is furthest away from the access point should the deck be completely disconnected from the property. The first board should be face screwed and when secure a hidden fastener clip should be secured into the groove on the top of each joist. When fully secure, slide the next board into place and after tightening with a rubber mallet, add another row of hidden fastenings. This process is simply continued until all of the deck is completely installed. If you arrive at the situation where the final gap does not perfectly accommodate a single board, the best solution is to cut some boards along their width into 2 equal pieces so they perfectly fill the space. Don’t forget to take into account the gaps needed between the previous board and the end of the deck though.

You’re finished!

Unless you are planning to add any additional structures such as a perimeter railing, or a pagoda you are now completely finished. You don’t need to do any kind of treatment or sanding to prepare the deck for use. If you want to arrange your furniture at this stage just get it into position. Otherwise just take a seat on the deck and marvel at your handiwork without any worry about whether the stain and varnish are dry, or if you are going to get a splinter somewhere unfortunate.

Should you have gone for wood?

This is the point of the installation that you will really appreciate the fact that you chose composite over timber. Now the job is totally finished and good to use. At the same point with a timber decking installation, you would now need to go through an intensive process of sanding the entire deck followed by a vigorous sweep to ensure there is no loose sawdust remaining. Next comes as many coats of wood stain as you think are needed, obviously waiting for them to dry in between each coat. A final coat or varnish will be the last step before you are done and can sit back and enjoy it. Until next year of course when you have to do it all again!