This project can fill up an entire weekend, depending on the extent of the repairs.
Cost
$100–$500
If you already own the tools, this DIY is a no-brainer.
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What you'll need:
TOOLS
Eye protection
Tape measure
Pencil
Speed Square
Circular Saw
Jigsaw
Oscillating saw (optional)
Miter saw (optional)
Hammer
Pry bar
Electric drill with bits
Screwdriver bit for drill
Regular screwdriver or small wood chisel
Small putty knife
End-cutting nipper tool
Socket set or adjustable wrench
Painting, staining, and sealing supplies
SUPPLIES
Replacement deck boards
Replacement railing lumber
2x4 pressure-treated lumber
2x8, 10, or 12 pressure-treated lumber
2½-inch Stainless steel or exterior-grade screws
3-inch Stainless steel or exterior-grade screws
Galvanized lag, carriage, or hex bolts and nuts.
16D galvanized nails
Wood putty (optional)
Water-based or epoxy wood filler
Clear wood sealer
Deck wood paint or stain (optional)
Joist hanger nails
Replacement joist hangers
While your deck looked shiny, new, and stunningly beautiful when it was installed, if it’s been a few years, it may have seen better days. However, learning how to replace deck boards and make minor structural repairs can add years to your deck’s life and seemingly transport it back to its glory days.
Even excellent wood deck maintenance can’t save it from needing some extra attention from time to time. Your deck has a big job to do, and sometimes the working conditions aren’t ideal, and deck problems can happen. Follow our step-by-step guide to replacing deck boards.
Prepping for Deck Wood Replacement
Replacing deck boards, making railing repairs, or fixing structure problems like deck board cracking requires a thorough investigation before heading to the store for materials. Make a list that includes detailed counts, measurements, and descriptions of the necessary lumber and parts. If you’re unsure of your deck’s wood species, cut off a small piece and bring it to the store for help making the determination.
Take Safety Precautions
Deck repair typically involves using power tools that can be dangerous if you use them incorrectly. Before using them, learn the safest way to use each tool, and wear eye protection whenever using them. Also, for this project, you’ll likely pry, pull, or otherwise manipulate wood that may not want to move. Wear eye protection when removing lumber or fasteners to protect yourself against flying fragments.
If your deck isn’t at ground level and needs a ladder to reach its underside, don’t attempt to perform structural repairs. For your safety, hire a local deck repair company to tackle this work.
Let’s start by ripping out your current deck boards. To replace a damaged deck board, use a speed square and pencil to mark a line at the edge of the joist at both ends of the rotten section. Use your jigsaw to cut on each line, then a pry bar, hammer, or drill to remove the board from the remaining joists.
Install New Deck Boards
To attach the new board, install a foot-long section of 2x4 with 3-inch screws flush with the top of the two end joists to support the board’s ends. Brush clear wood sealer on all cut ends. Then install the deck board with 2½ screws in each joist below. Be sure to maintain a staggered pattern as much as possible and span at least two joist spaces for each repair. Stain or paint the new wood to match the rest of the deck.
Repair Rotted Wood
After removing the rotten deck boards, you may find wood rot on the top of the joist below, or you may need to repair a small spot on a deck board or railing. To fix the spot, dig out the rotten material with a regular screwdriver or small wood chisel and allow it to dry if it’s damp.
Then, fill the spot with water-based or epoxy wood putty and level it with a putty knife. You should allow it to dry before installing the deck board or using the area.
Fix Protruding Fasteners
The best way to deal with nails or screws that stick above the deck boards is to remove them and replace them with longer screws than the original fastener or create a new hole and install a new screw. If the head of the nail or screw is broken off or too corroded to remove, clip the head off with an end-nipper tool, and drill a pilot hole next to the fastener. Drive a new screw into the hole. The new screw will camouflage the old hole and fastener.
Loose railings often result from loose or worn nails or screws or rotten railing boards. Tighten any loose screws you can find and replace any nails or corroded screws. However, there is little you can do with rotted railing wood.
If you find that’s the culprit, remove the rotten section and replace it with the same type of lumber or material. Replacing a porch or deck railing costs an average of $925. Stain or paint the new wood to match the rest of the railing.
Tighten Loose Posts
As wood dries out, it shrinks and can cause posts in otherwise good condition to become loose. Sometimes, simply tightening the nut and bolt or lag screw with a socket wrench or adjustable wrench can eliminate the problem. If not, remove and replace the bolts or lag screws, one at a time, by drilling expanded holes to fit slightly larger replacement hardware.
If you still experience loose posts, cut two pieces of wood that match the joist dimensions to fit between the joists at the post. Install them with several 3-inch screws under the deck, in the joist space directly against the post. Drill pilot holes and drive lag screws through the new blocking and into the post.
Replace Corroded Hangers
Over time, galvanized joist hangers can rust away and leave the deck feeling spongy, which is a dangerous condition. From under the deck, support the joist end with blocks or a jacking device and remove the old hanger and nails with a pry bar. Be patient with this part; it’s not easy work. With the temporary support still in place, replace the hanger and fasten it with hanger nails.
Sister a Joist
By the time you need to sister a joist to maintain the integrity of the deck, it usually means there’s serious trouble with the existing joist you’re trying to repair. Before attempting the task, strongly consider having a professional inspect the situation and perhaps allow them to perform the work.
However, if you’re going to do it anyway, cut a new piece of lumber of the same dimension and support it directly against the existing joist. Nail in three 16D nails every sixteen inches over the entire board length. You may also predrill holes and use two lag screws or bolts every two feet if nailing between joists is too difficult. Don’t use decking screws to sister joists since they don’t have adequate sheer strength to support the sideways joist pressure.
DIY Deck Repair vs. Hiring a Pro
DIY deck repair can eliminate the cost of labor of hiring a professional. However, there are many situations where calling a local deck repair specialist to inspect your deck and provide solutions is prudent and necessary. If your deck connects to the second story, has more than minor structural problems, is experiencing loose stair components, or you’re unsure of the problem, calling a pro for help is always better than risking your safety.
Occasional repairs and deck maintenance are much less costly than replacing the whole thing. DIY deck repair saves you the labor cost, typically between $40 and $140 per hour, representing about 40% to 50% of the total cost of professional repair. The cost to repair your deck can range from $1,890 to $6,500, depending on the extent of the damages.
Frequently Asked Questions
If you have a painted wooden railing on your deck, paintable exterior-grade latex or acrylic caulk can fill in gaps within the wood or in joints between pieces. Let it fully cure before applying new paint to match the existing color. Alternatively, you can use various colors of wood putty in gaps to match the existing color.
You can use caulk as a wood filler in some cases. However, it doesn’t accept wood stains and creates an unsightly repair on stained decks. It’s excellent for use on painted decks. Remember that caulk isn’t a structural filler. It can’t hold onto a screw or nail and deforms under more than a small amount of pressure.
Wood putty and wood fillers are excellent products, but their application is different from one another. Wood putty remains relatively flexible after installation, making it the best choice for exterior applications such as deck repair. Wood filler, on the other hand, dries hard after installation and becomes brittle with temperature fluctuations. Typically, wood filler is for indoor applications unless the product specifically states that it’s usable outdoors.
Deane has spent 30+ years in residential construction, contracting, remodeling, maintenance, and home repair, and now contributes DIY and educational articles for publications like Forbes Home and U.S. News. Throughout his career, he has strived to help homeowners find the potential hidden within the walls of every home and empower them to take control of their household repair and remodeling endeavors.
Deane has spent 30+ years in residential construction, contracting, remodeling, maintenance, and home repair, and now contributes DIY and educational articles for publications like Forbes Home and U.S. News. Throughout his career, he has strived to help homeowners find the potential hidden within the walls of every home and empower them to take control of their household repair and remodeling endeavors.
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