Can I Use Tongue and Groove Boards for Decking?

Can you build a deck with tongue and groove boards?


The answer is yes. Creating a deck with tongue and groove lumber is as easy as creating a deck with traditional boards. First, cut all of your pieces into appropriate lengths.

Next, coat any fresh cuts with an end sealer. This will ensure the end cuts don’t release moisture too fast (which reduces the changes of cracking or splitting.

Once your first board is in place, the rest of the job will go smoothly as you just need the other boards to fit snug into one another. If you need help fitting the boards into one another, use a grab clamp or two to help keep the boards in place. For installation, we suggest that you pre-drill a hole on a 45-degree angle where the tongue and the face meet. You will see a slight v-groove in this corner. Then, on that same 45-degree angle, drive a trim head screw through the pre-drilled hole, through the deck board into the floor joist.  The trim head screws are required because the head will sink into the corner where the v-groove is. This sinking action will allow the next deck board to slide into place and will perfectly conceal the previously installed screw head.


Some helpful tips to remember when using tongue and groove lumber for decking:

  • You must have 24” or more of open air space below the deck to use tongue and groove boards.
  • Leave at least 2 sides of the upper deck space open for cross ventilation.
  • Tongue and groove decking should be used for covered porches and patios only.
  • Do not allow standing water to collect under the deck. Ensure that the ground is adequately sloped under the deck to eliminate standing water under the structure.
  • If you install skirting around the perimeter of the deck, it is imperative that the skirting does not prevent cross ventilation.

When choosing your tongue and groove lumber, remember Ipe is a strong, dense material that is great for any outdoor project. Get your free Ipe decking quote directly from the mill. Contact today. Happy decking!2

8 thoughts on “Can I Use Tongue and Groove Boards for Decking?

    • I assume you meant t&g ipe decking. No, tongue and groove decking must be installed in a covered area. Because t&g has no gap between boards, rain will pool on an uncovered surface and cause distortion. The increased moisture buildup will cause greater movement in the boards, and without gaps they’ll have no room to move, causing them to cup and warp.

    • No, just the ends.

      To clarify, the sealing we’re talking about hear is a wax coating that keeps water from getting in or out. This is different from an oil finish that you use on the board surface to “seal” the color.

  1. I’m in the Pacific Northwest and we have rainy, damp winters. My house is a Craftsman bungalow, and I need to replace the porch flooring. It’s a covered porch, but I do get rain blown in on the outside 12″ or so of the porch floor when it’s windy. Is that a concern?

    Also, how much ventilation is needed underneath? The porch has siding all the way around; it’s not quite flush to the ground in some spots, but there’s probably not more than 2 square feet of openings to ventilate the underside, all in gaps between the siding and the ground. Is that enough ventilation to prevent the ipe from buckling?

    Finally, is the t&g interface tight enough to keep water off the joists?


    • The tongue and groove should be fine as long as the porch is pitched and has a good covered roof over it. If it usually sees some rain on the outer edge around 12 inches shouldn’t be a problem if it’s pitched for drainage. If the water sits on it and puddles without draining you could see some undesirable movement. We recommend a minimum of 18 inches of ventilation, if it’s all skirted off with siding and does not allow for some sir movement you could see cupping as the underside of your deck could have higher moisture and humidity then the top of your deck that’s exposed to moving air. We recommend using DeckWise joist tape on your joists before installing that will help prolong the life of your joists.

  2. We’d like to build a ipe fence WITHOUT gaps (for privacy – nosy neighbors). We’ve read the concerns about ipe tongue and groove for deck applications and that it should only be used where covered. But for a fence it would be fully exposed to air on both front and back sides with minimal water retention, possibly some seepage into the joints. But it would be exposed to southern California summer sun. Would ipe tongue and groove still have problems in this situation? We are thinking horizontal boards for the fence. Thanks!

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