What to put under our new metre high deck?

jenib

We have just had our decrepit old deck replaced with a beautiful new deck, approximately 1 metre off the ground.   With the old deck, there were various weeds and plants underneath and our dogs loved playing under there, often getting muddy or wet, chasing creatures at night.

With the new deck we would like to put gravel or small stones under there and we are wondering whether to use weedmat or geotextile then the stones or just the stones.  Does weedmat really work or is it a recipe for plastic waste in the future?  Would recycled shadecloth work instead?  It will be fairly difficult to place the stones as the deck is almost 3 metres wide and I've heard of people using a wide pvc pipe as a funnel to place the stones without having to lug them underneath as far.  Any other tips for getting the stones into place (the deck is already complete) or other ideas for a low maintenance, vermin free area under the deck?   

MitchellMc

Welcome to the Bunnings Workshop community @jenib. It's a pleasure to have you join us, and many thanks for your question about finishing under a deck.

That sounds like a great upgrade, and it’s terrific that you're thinking ahead about keeping the area under the new deck neat, low-maintenance and dog-friendly.

Weedmat or geotextile fabric can help reduce weed growth under stones, but you’re right to question the long-term environmental impact. Over time, many weedmats degrade, especially if exposed to UV or if organic matter settles over them, creating a layer where weeds can still germinate. Recycled shadecloth could be a reasonable alternative—it’s breathable and allows water to drain while still providing a barrier that may reduce weed growth. Just make sure it’s tightly secured and overlaps well to avoid gaps.

If you want a long-term solution, using a heavier-duty geotextile fabric rather than standard plastic weedmat is probably the better choice. It's designed to last longer, won't break down as quickly, and still allows for good drainage—important if you’re putting gravel over it.

As for getting the stones in, the wide PVC pipe trick is a good one—cut the pipe at an angle at one end so you can rest it on the ground under the deck and funnel stones through it from outside. You might also consider a long-handled shovel or even a top soil spreader to push smaller gravel into hard-to-reach areas.

To help discourage vermin and keep the space tidy, a 50–75mm layer of gravel is usually enough. Make sure the ground under the deck is graded to prevent water pooling, especially if you’ve had mud issues before. You could also install some low skirting or mesh around the perimeter to stop larger animals getting in while still allowing airflow under the deck.

Please let me know if you have any questions.

Mitchell