Framing for your deck

GAV-SAX Framing 202308 06

A new deck can transform your garden, creating an outdoor living space to enjoy all year round, year after year. First you will need a well constructed frame for the decking boards to be fixed too, otherwise your deck could become uneven and hazardous to use. When we build your deck, we first construct a solid frame from either treated timber, plastic or aluminium. This supports the main structure of your decking, acting as a foundation. It consists of creating connections between joists, beams and support posts, on which the decking boards are fixed to. The frame is built to take most of the weight from the decking and ensure the finished deck is safe and sturdy.

We use HDPE plastic framing, timber framing or aluminium framing. Sometimes we use a hybrid approach using different materials for the framing.

HDPE Plastic Framing

DPE, or High-Density Polythene, is made from recycled material that will not rote, swell or split like wood, making it a suitable solution for deck near water and damp environments. The benefit of this type of framing is the it will last any warranty of 25 years.

Plas-Pro is Millboard’s premium 100% recycled subframe material. This all-weather, durable and flexible material is a non-rotting alternative to timber. This makes it an appropriate frame to use around water and damp environments.


Timber is the traditional method of constructing a decking frame. We use C24 timber, which is UC4 treated softwood as apposed to C16 (industry standard). This makes sure the frame last just as long as the Trex/Millboard decking on-top. C24 vC16

This type of framing is used for decks over 300mm in height, to avoid it being exposed to wet or dampness from the ground as timber can be prone to rotting if exposed to wet or damp conditions. However, to protect the timber joists we apply cut end sealer and Walther Strong deck tape. This helps to maximise the lifespan of the frame, enabling to you enjoy the deck with little maintenance required.


Aluminium has a superb resistance to fire and is both long-lasting and easy to work with. It won’t warp, sag or rot and will easily outlive the life of your decking boards. It can also span greater distances, unlike timber frame.

Millboard’s DuoSpan combines the strength or aluminium with the design flexibility of recycled plastic. It is resistant to rot, warping or twisting and an ideal framing structure around high-moisture areas.

Supporting the frame

The frame is supported by a number of possible options dependant on the space between the bottom of the frame and the ground. We use a number of different methods including Steel Post holders / brackets and shoes, Plastic and Aluminium Pedestals, HDPE and/or Timber UC4 Treated Posts, Steel Ground Screws. All of the supports we use are placed or fixed to solid ground and in some cases are fixed onto Concrete pads or Forms. No structural timbers come into contact with the ground.