Can You Put Composite Decking Over Wood Frame?

If your deck has seen better days and years’ worth of sun damage and rain are taking their toll, you have a few options. In some cases, refinishing the deck will bring it back to life, but the damage may be too extensive. So, you could rip it out and build a new one, though this will be expensive.

You can install composite decking over the old wood frame if it is still structurally sound. This saves you from having to rebuild the entire deck, but it’s not a good idea if the existing frame is beginning to rot. Ensure a proper inspection of the frame is completed. 

Before putting composite boards over the old deck, you need to consider what condition it is in and whether it has been treated or not. This article will explain how to put composite decking over your wood frame, and whether it is a good idea in the first place.

How to Resurface Your Existing Deck with Composite (Step by Step)

If you have an existing deck and you’re looking to resurface it with composite, there are a few things you need to do first. Here’s a step-by-step guide:

1. Remove Existing boards

This should be relatively easy to do with a pry bar. Most of the time, the nails come straight out as you pull the boards up, but double-check the joists afterward and remove any stragglers.

2. Check the Frame for Damage

If there are any parts of the frame that are damaged, they need to be repaired with filler before you put the composite boards over the top. You may also need to reinforce the frame so it can support the extra weight. Do this by adding more joists if necessary.

3. Sand Down the Frame

Use a belt sander to sand down any splinters or rough patches on the frame. This will make it easier to work with and if you decide to use an adhesive, it will stick better. Just bear in mind that you shouldn’t use an adhesive as your main method for fixing the boards, it just adds a little extra grip.

4. Apply Wood Sealant

If the frame isn’t already treated, you’ll need to do this before putting the composite boards over it. A heavy-duty wood sealer will keep out the moisture and prevent mold and mildew. You can also get joist protection tape which adds more moisture protection and covers small holes left by old nails. See our 10 recommended wood sealers for exterior wood

5. Install the Composite Boards

cutting boards with a jigsaw

First, cut the ends of the boards and then cut them to size using a jigsaw. Then, you simply need to put them in place and screw them into the joists. Make sure that you use exterior-grade screws that will hold up against the elements.

Leave small gaps between each board too, so rainwater drains easily. You can use small plastic spacers to make sure that the gaps are the same on each board.

Follow these basic steps and you can resurface your deck with composite boards. The plastic-wood composite is very durable and weather-resistant, so you don’t need to treat it right away. But it is worth using a sealer after a year or two to give you more protection and make the deck last longer.

How Much Does It Cost to Resurface a Deck with Composite?

Naturally, this depends on the size of the deck. But on average, it costs around $15-25 per square foot to resurface a deck with composite. This includes the cost of materials and labor. So, if your deck is around 500 square feet, it will cost you between $7,500 and $12,500 to resurface it with composite.

This is a lot less expensive than rebuilding the deck from scratch, but it’s still not a cheap project. That said, it’s a relatively simple job to do yourself, so you can save money on labor costs. Labor averages around $50 an hour, depending on where you live, so you could save a significant amount by doing it yourself.

If your deck is in bad shape and needs a lot of work, it might be better to just rebuild it from scratch because you will have to pay for repairs in the near future.

Can You Put Composite Decking Over Existing Deck?

Yes, technically, you can put the new composite boards directly on top of the existing deck. They simply need to be screwed in once you have cleaned and prepared the wood underneath. 

Should You Though?

The short answer is, no. If you put composite decking straight over an old wooden deck, you create small gaps where water gets trapped. This only accelerates the rot that has already started to set in around the frame, making the deck dangerous. You need to remove the boards so you can check the structural integrity of the frame and fix it before you fix new boards.

Can You Install Composite Decking Over Plywood?

Yes, you can install composite decking over plywood. In fact, it is actually a good idea if you want to improve the stability and strength of the deck. The thin layer of plywood, installed before the composite decking, will help the weight to distribute more evenly and make it more stable.

Final Thoughts

There are a lot of things to consider when resurfacing your deck with composite boards. But if you take your time and follow the basic steps, it’s a relatively simple job to do yourself. Often, it is a better alternative than rebuilding the entire deck, but only if the frame is in solid condition.

Read our related articles about composite decking: 

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