Pier installation details (C) Daniel FriedmanDecking Installation Tips
Deck Design-Build Online Guide

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How to install deck boards: tips from the pros: here we explain how to handle crooked or twisted deck boards, thick 2x6 deck boards, tongue-and groove decking and other special problems that you may encounter when installing a deck floor or decking boards. We also discuss how to best notch deck boards around obstructions like trees or access panels.

The article finishes by describing how to finish off the final trimming of the ends or edges of the deck boards, a step that leaves the floor edges and lines looking perfect. This article series describes construction details for decks and porches including methods for installing decking or deck b boards.

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Decking Installation Tips: how to install twisted deck boards / floors, notch around obstructions & more

Pier installation details (C) Daniel Friedman

For the most part installing decking is a relatively easy and straightforward part of deck construction. If your decking hoards are all straight, your deck frame is a perfect rectangle, and a railing is not needed. But most deck builders are going to have to deal with unruly boards and obstacles that require special care.

Our photo of the Two Harbors MN Summerblue Arts Camp stage floor decking installation (above left) illustrates using tongue-in-groove 2x6 deck flooring.

Working with these boards was hell: there was no choice of "best side" as asymmetric cutting of the tongue-and groove position means there is only one "up" side for each board.

To straighten each board before nailing we used a combination of clamps, temporary blocking and pry barr or as our photo shows, brute force.

Watch out: take care when forcing deck boards into position not to gouge up the edges of your boards, especially if you are using tongue-and-groove treated wood as we were in this project. Smashing up the tongue or grooves of a deck board can make it impossible to fit the next board snugly.

Decking forcing tip: Our trick when using a pry bar or hammer to force a T&G deck board into place was to use a short section of tongue-and-groove decking as a block against which to pry the actual deck board. This confined damage to our pry block and left the deck board edges intact.

How to Force Deck Boards into Position

Deck board wedging tool used with heavy deck boards (C) Daniel FriedmanIf you are installing wood decking, chances are very good that many of your boards will be bowed, some more than others. (One of the advantages of composite decking is that you are not likely to face this problem.)

To install heavy 5/4 or (as shown at left) 2x6 tongue-and-groove decking we made the simple board wedging tool shown at left. For the most curved deck boards we tacked our wedge across two joists and used the 2x4 as a pry bar against a T&G scrap that was in turn used to prevent damage to the deck boards.

By tacking the wedging apparatus a few feet away from the working edge of deck board installation, and by using additional scraps between the 2x4 pry bar and the secured edge of our wedging tools, we could install several deck boards straight and tight before having to pull up and relocate the wedge device.

To maintain a consistent gap between the decking boards, that means some will require a bit of persuading to get them into alignment. Moderately bowed boards can usually be pulled into line with one hand while driving a screw or nail with the other. More difficult boards may require other techniques.

Whichever method you use, remember to place a spacer between the boards before pulling the problem board into place.

A flat pry bar or utility chisel can be used to straighten most thinner deck boards than those we just described above. Knock the sharp end into the joists at an angle, and then pull the board toward you. Hold the pressure on the board until the fasteners are installed. If you are working alone, start the fasteners before pulling the board in.

When prying by hand fails to move the board far enough, a pipe damp is a good alternative. Hook one end against a pry bar stuck between two boards and the other end over the edge of the problem board. Tighten the clamp until the board is properly aligned. Fasten the board, and then remove the clamp.

If you are building a large deck and have a plentiful supply of bowed boards, it might be worth investing in a specialized tool. Buy one that hooks over the joists, and then pulls the board into line quickly and with little effort.

Tongue and Groove Decking Installation

Tongue-and-groove composite decking is installed much like hardwood flooring used indoors. Fasteners are driven through the grooves, which are then covered with the tongues of subsequent boards. This type of decking is installed beginning at the outside edge of the deck, working toward the house. You’ll need to add fascia boards on the three exposed edges to hide the decking edges.

1. Install the Starter Strip

The starter strip is attached at the far end of the deck, with screws driven into the rim joist. The strip must be straight and parallel with the side of the house.

2. Attach the Decking

Slide the tongue of each new board into the groove of the installed board (or, to begin with, the starter strip). The decking is designed to create a ¼ inch gap between boards. Drive screws through the tongue of the board and into the joist.

3. Install the Last Row

If a full board fits comfortably in the row next to the house, drive screws vertically through the groove section. Otherwise, rip the board to fit and attach it to a 1-inch-square block of wood. As for any decking, allow a 1/4-inch gap between the decking and the house. Attach fascia boards to cover the edges of the decking.

Why & How to Notch Deck Boards Around Obstructions

Deck plan had to cut around these trees (C) Daniel FriedmanMost decks have obstructions that require decking to be notched. These include posts for railings or overheads or legs for built-in seating. Many of these supports need to be installed before you finish the decking.

It was important to preserve the trees shown in our Green Cabin project photo (left). This meant that the ground-level deck planned for this area would need to be cut around these obstructions, leaving clearance for green growth, the roots or bole of the tree.

These methods can be used on solid decking, whether wood or composite. For other decking materials, check with the manufacturer before cutting notches.

1. Mark for the Decking Notch Cut

To mark an accurate cut line in a board that needs to fit around a post, set the decking in place against the post. With an angle square or combination square, mark the post location on the decking.

Low deck with openings for trees (C) Daniel FriedmanOur photo at left shows the ground-level deck in place. We cut around the center tree to the left of the cabin entry door. The deck layout simply chose to avoid the second right-hand tree completely. Notice that our little deck gives two methods of entry: a single low step (at front right) or an accessible ramp (at front left).

2. Make the Deck Board Notch Cut

Cut the notch with a jigsaw. Cut a little to the outside of the marks so that the notch is not too tight.

3. Add Support at Cut Decking Ends

You always need to support cut ends of decking. When notching to fit around a post or another obstacle, attach cleats to serve as supports, and then drive fasteners through the decking and into the cleats.

Tips for Trimming Deck Floor Boards

It is much more efficient to cut the decking to length after it has been installed. Measure and mark the end boards for any overhang you have planned (typically 1 inch), then snap a chalk line to guide your cut. If you are concerned about being able to make a straight cut, tack a 1 X 4 to the deck surface to guide your saw. Follow the same method for any decking material.

1.Trim the Ends

Carefully follow the chalk line to cut the decking to its final length. You can finish cutting near the house with a handsaw or jigsaw.

2. Smooth the Deck Board Cuts

Clean up the edges with a power sander, or use medium-grit sandpaper wrapped around a block of wood.

How to Handle Left-Over Deck Flooring or Framing Lumber

If you wind up with a pile of short pieces of cut-off decking, you need to dispose of these leftovers properly. Pressure-treated wood and composite or vinyl decking should never be burned. In most areas, you can dispose of unneeded scraps with normal household waste. Larger pieces of decking, however, can be used to build small planters or tables for use on the deck or around the yard.


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