The number one reason why most of our customers who ask us to replace their deck’s floorboards with composite boards who can’t is…Composite boards are extremely thin (most brands), and have a lot of flexibility in them. Have you ever seen anyone carrying these through Lowe’s or Menard’s? Both ends are always touching the ground. The maximum joist spacing your deck can have from center to center is 16 inches, and the manufacturer doesn’t recommend a spacing greater than 12 inches. Decks in Michigan originally built with wood almost always have a 20 inch or 24 inch gap between joists.
You might be in luck though. If your deck is square-shaped, you can pay a bit extra to have us or another reputable deck builder move the existing joists closer together and fill the extra space with a few new joists.
Other things to consider: Composite boards cost almost double of the cost of wooden boards and will not last longer than the lifespan of 2 new sets of wooden boards. Do your online research before choosing a composite decking brand…some brands have class-action lawsuits against them for selling product that only lasted a couple of years before rotting away. Stain does not stick to composite real well (although it can be done after the boards have aged a couple of years), so be very sure you’ll still love the color 10 years down the road. They also tend to get unmanageably hot in the summer sun.
We recommend only using composite deck boards in areas that see a lot of moisture, i.e. near the ground, around heavy foliage, or on docks.