We created this sunken deck in Old Coulsdon, Surrey, using a Millboard Plas-Pro composite subframe beneath Millboard Limed Oak decking, avoiding the risks associated with installing timber in a poorly ventilated, below-ground position.
The client did not want timber used for the supporting subframe and opted for a composite alternative. As the deck sits below the surrounding ground level, this was also the solution we would recommend for the location.
Timber positioned below ground has very little airflow around it, which makes it difficult for moisture to dry. Over time, these damp conditions can lead to decay within the supporting structure, even while the deck boards above still appear sound.
We constructed the subframe using Millboard Plas-Pro recycled plastic lumber, which will not absorb moisture or rot like timber. This created a more appropriate and durable foundation for the sunken deck.
With the Plas-Pro subframe in place, we finished the project using Millboard decking in Limed Oak. Its softly weathered colouring and detailed timber appearance brought a lighter, contemporary finish to this Old Coulsdon garden.
By combining Millboard decking with a completely non-timber subframe, we created a low-maintenance installation designed around the challenging below-ground conditions rather than simply relying on a standard timber construction.
If you are considering replacing an old deck or creating a new outdoor living space, we can help. We design and build high-quality composite and timber decking throughout Surrey, South London and the surrounding areas.
Call us on 07756 269011, email hello@deckanddesign.com, or complete the form to tell us about your project.
A deck positioned below the surrounding ground level often has limited airflow, so damp timber can take much longer to dry. These conditions increase the risk of decay within the supporting structure, which is why we may recommend composite or recycled plastic lumber instead.
Millboard Plas-Pro is a recycled plastic subframe system used to support decking. It does not absorb moisture or rot like timber, making it particularly useful for low-level, damp or poorly ventilated installations.
Yes. Good drainage and ventilation remain important, even when non-timber materials are used. We plan the structure so water can escape and moisture is not unnecessarily trapped beneath the deck.
Yes. We design and install composite decking in Old Coulsdon and throughout the surrounding Surrey area. We recommend the subframe and decking materials according to the location, ground conditions and available ventilation.
