A NeoTimber® guide to everything you need to know about installing composite decking on concrete.
When laying composite decking over a hard surface, like concrete, it can be tempting to cut corners and lay the decking directly onto the concrete avoiding the extra work of securing a proper composite decking subframe. A golden rule that you should live by, however, is to never install composite decking without a subframe. There are numerous reasons why this is a bad idea, and we outline these below.
Every composite decking solution requires a framework to ensure ventilation and structural integrity. What’s more, concrete is not always level and so securing your boards directly to it would mean that your deck would be out, too. Another key reason to install a subframe is because, despite the long lifespan of NeoTimber® composite decking, excessive water build-up would deteriorate the product at a quicker rate. Therefore, a joist subframe of no less than 35mm is strongly advised.
You can install composite decking onto concrete, if you install a subframe for the composite deck boards to sit on first. This article will assist you with all the information you need to go about this.
Why A Subframe Is So Important
A well-built subframe offers structural integrity to your composite deck, giving it rigidity and support so it has room to flex under changes in temperature and changing weight loads. Giving even support to the boards, there are no stress points or areas under greater strain as the subframe works cohesively, directing force and pressure along its joists to spread the load.
Most importantly, however, a subframe creates a vital space beneath the deck boards, where water can easily drain away, and air can pass through. This airflow allows boards to dry much quicker, making for a safe, long-life deck.
Our Composite Joist Is The Ideal Fix For Composite Decking On Concrete
Whilst timber is widely used as a subframe for standard wooden decking, issues can arise when placed directly onto a hard surface as standing water can cause rot to set in. We do sell no-maintenance joist tape which protects the upper surface of timber, but this has been introduced to assist those wanting decking on a low budget. The ideal option is to use our composite posts and joists, here we list some of the reasons why composite is a better option to timber:
Longer life
Composite, as you may imagine is a composition of more than one material, in this case wood and plastic. Each complements the other, wood with its strength and rigidity and plastic with its waterproofing and flexible properties combine to create a resilient, strong, weather-resistant ‘super wood’, that we call NeoTimber®.
NeoTimber’s custom-designed WPC (Wood Plastic Composite) joist is the perfect solution for fixing decking to a solid base. Designed specifically for fixing into concrete, it can be fixed lengthways, drilling directly into the concrete itself, saving the need for sinking posts.
Purpose Built For Drainage
You can install a WPC subframe without any fear of it warping or cracking. WPC Joists are hollow and have a drainage hole built-in to allow for water runoff. Assuming that your subframe may be sitting in water for an extended period of the year, WPC Composite Joists perform far better than their timber counterparts as they absorb significantly less water, reducing the warping effect.
Easy To Install
Our NeoTimber® WPC Joists are easy to install, as you can drill straight through them and attach them to your concrete base. Simply drill through using a countersunk screw and fix at 500mm increments. You can then attach the deck to the joist board using our custom-engineered clip system which fit down a guidance channel along the length of each joist.
Our WPC Joist is just one subframe product we offer. In fact, we have numerous widths of joist available, according to your requirements. Browse our full range of long-life subframe solutions here.
Raise Your Deck Higher (Without Posts), Using Our Custom-Built Pedestals
Adjustable between 18mm and 310mm they can easily accommodate uneven surfaces, steps and variations in ground level. Whether building your deck to reduce the step out of a patio door, re-level uneven steps or introduce terracing to a sloping garden, our NeoTimber® adjustable pedestals can assist you. Custom-designed to fit perfectly with our small joists, they work together with your decking to provide the perfect subframe for raised decks on concrete bases.
Need Further Support or Advice?
If you’ve still got questions that have not been answered here, or you would like additional advice,
support or assistance then please give one of our friendly experts a call and we’ll be happy to help.
Just give us a call on 01530 382 180.