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Build a Deck

Build a Deck

Decks styles and sizes are as varied as the homes they are attached to. Learn some deck-building basics - good information to know whether you do it yourself or hire a professional.


Deck Building Terms

Deck Diagram

Here are some of the terms you'll need to know to complete this project:

Beam: A horizontal support member (Also see post.)

Decking: The material installed over the supporting framing members to which the roofing material is applied

Edge: Either of the two longer sides of a board, perpendicular to the face

Face: Either of the two wide surfaces of a board

Footing: The base on which a masonry wall or other support rests. It spreads out the load to prevent settling

Joists: Horizontal framing members that support a floor or ceiling.

Pilot Hole: A small-diameter hole that guides a nail or screw

Post: Any vertical support member

Rim Joist: The outermost joist in a structure's floor framing

Rise: The vertical distance from one point to another above it; a measurement you need in planning a stairway or ramp (Also see run.)

Run: The horizontal distance a ramp or stairway traverses (Also see rise.)

Screed: Leveling concrete, sand or other material by pulling a board pipe or other straightedge across it in a sawing motion

Three-Four-Five Triangle: An easy, mathematical way to check whether a large angle is square. Measure 3 feet along one side, 4 feet along the other. if the corner is square, the diagonal distance between those two points will equal 5 feet.

Toenail: To drive nails at an angle.

Shop Decking

Check your local building codes or Home Owner's Association regulations before planning or building a deck.


Designing a Deck

Planning is a crucial step in any construction project. A good plan serves as a reference throughout the project. Use the following suggestions to help with the planning process:


Step 1

Determine where you want the deck. What are the critical dimensions? (length, width and height) Are stairs necessary? If so, where will they go?


Step 2

There are a few ways you can plan your deck:

  • Use graph paper to sketch a scaled drawing. Use the drawing to generate a materials list.
  • Go to your local Lowe's and give the critical dimensions of the deck to an associate at the project desk. The associate can generate a complete project guide for you which includes a Lowe's project planning guide, plan view, dimensioned plan view, post layout view, dimensional view and a complete materials list. Complete package pricing is also available.
  • Use our Deck Designer to custom design your new deck.

Step 3

Take the project guide to your local building inspector. The inspector will review the plans and advise you of any changes needed. The inspector also will advise you of any special permits and building requirements for your area. Take notes and ask for copies of special instructions pertaining to your project. Find out what inspections are required for the project. Make sure you know the procedures for setting inspection dates. Spend extra time planning and gathering information to prevent making changes in the later stages of the project.



Laying Out the Deck


Step 1
Mark the Elevation for Your Deck Surface

Mark the elevation for the finished deck surface. Keep in mind that most deck surfaces run 2 inches to 3 inches below the bottom of the door sill. Measure down to account for the thickness of your decking material and make another mark. This mark represents the top of your ledger board. Measure down again for the width of your ledger board and make a mark. This mark represents the bottom of the ledger board and the top of the beam.



Step 2
Use the 3, 4, 5 method to check for square.

Using a water level, transfer each of the three marks to the left and right edges of the deck. Snap chalk lines to represent the top and bottom of the ledger board.



Step 3
Use mason's cord to check for level.

Partially drive nails into the wall, even with the left and right edges of the proposed deck. If the elevation is too high to work with comfortably, use a level to transfer a mark 2 feet to 3 feet off the ground, then partially drive nails at the marks.



Step 4

Drive batterboards into the ground approximately 2 feet past the proposed deck depth. Center the batterboards on the left and right edge marks for the deck. Use a tape measure squared to the house to determine the location of each batterboard. The crosspiece of each batterboard should be parallel to the house.


Step 5

Use the three-four-five method to check for square. Cut a piece of mason's cord approximately 3 feet longer than the proposed deck depth. Tie one end of the cord to the nail marking the left edge of the deck. Have a helper pull the cord to the batterboard. Use the following method to square the cord to the wall.

Measure 3 feet along the house and mark that spot on the wall. Measure 4 feet from the house along the cord and mark the spot with tape. Measure between the two reference marks. Adjust the cord on the batterboard until the distance is 5 feet. Drive a nail into the batterboard and tie the cord to it. Attach a line level to the cord, and move the batterboard up or down as needed to level the cord. Make sure the cord is square with the house. You now have a level line squared to the house. Perform the same steps on the right edge of the deck.


Step 6

Measure the proposed deck width, minus 1 foot, from the wall along the cords on the left and right edges of the deck and mark them. Drive in the batterboards 3 feet outside of the two existing layout lines. Cut a piece of mason's cord, and tie it to the two new batterboards.

The cord should intersect the marks you made for the proposed deck width on each of the first two cords. Adjust the batterboards so the last cord you tied just barely touches the tops of the left and right edge cords.


Step 7

You now have three squared and level lines. The corners where these lines meet represent the outside edges of the corner posts. The local building inspector can tell you how many posts you need and the maximum distance allowed between them. Mark the ground with stakes or spray paint where you need to dig footings for the posts. Untie and save the mason's cords. These will be useful later when you stand the posts.



Digging the Deck Footings


Step 1

Dig your footings so they reach below the frost line. Your local building inspector can give you the information you need pertaining to the depth, diameter and shape of your footings. Some codes may require the bottom of a footing be wider than the top.


Step 2

Use posthole diggers or a power auger to dig the footing holes. It takes two people to handle a power auger, so if you choose this option, get a helper.


Step 3
Pour concrete footings.

After the building inspector approves the footing holes, you're ready to pour concrete. At this point, decide whether to use tubular concrete forms or pour the concrete directly into the holes. If you elect not to use a form, you can still obtain a professional-looking finish. Place a 4 inch or 5 inch section of a form over the exposed portion of the footing, and then level the concrete with a board. Work the board back and forth as you pull it across the top of the form. Leveling concrete in this manner is called screeding. You must also decide whether to order concrete or mix it yourself. The determining factor will be how much concrete you need.



Step 4
Set J-bolts in wet concrete.

To determine the number of 60-pound bags needed to fill a 12-inch-diameter hole, divide the depth of the hole in inches by 9. To determine the number of bags needed to fill all the footing holes, multiply the number needed to fill one hole by the number of holes.

D = depth of hole in inches
N = number of bags per hole
H = total number of holes
T = total number of bags
D / 9 = N
N x H = T



Step 5

Fill the holes with concrete and screed the tops level. Replace the mason's cords, and use a plumb bob to find the centers for each post. Set J-bolts in the wet concrete. Leave about 3/4 inch of the threaded portion sticking up where the post centers will be. Allow the concrete to set. Depending on the size of the holes, it may take up to three days for the concrete to set.

Before you begin any excavation, you need to call and check for underground utilities. The North America One Call Referral Service (1-888-258-0808 or just dial 811) connects you to a national directory of utility companies.


Hanging the Ledger Board


Step 1

Lumber is usually 1/2 inch to 1 inch longer than its stated length. The extra length allows you to square boards and maintain their nominal length. Cut the ledger board, ribbon joist and the two boards for the beam to the required length. Use a combination or framing square to mark the ends before you cut them. The ledger board, ribbon joist and the boards for the beam should be the same length.


Step 2

To mark the joist locations, lay the four boards you just cut across two sawhorses with the crown edges facing you. Most boards have a slight bow to one edge. The high side of the bow is called the crown or crown edge.

Align the crown edges and ends of the boards and clamp them together securely. Measure in 1 1/2 inches from the left side of the boards and make a reference mark. Put an X to the right of the mark. Measure in 15 1/4 inches from the left side of the boards. Make a reference mark, and put an X to the right of it.

After these first two measurements, continue marking the boards every 16 inches until you run out of board. Hook your tape measure on the left edge of the boards. There should be marks at 1 1/2 inches, 15 1/4 inches, 31 1/4 inches, 47 1/4 inches, 63 1/4 inches, 79 1/4 inches, etc. Measure in 1 1/2 inches from the right side of the boards. Make a reference mark and put an "X" on the left side of the mark. Each mark represents the edge of a joist. Each "X" denotes the side of the mark where the joist attaches.


Step 3

Transfer the reference marks and Xs to the other three boards. Unclamp the boards and transfer the reference marks and Xs from the edges to the faces of the ledger board and the ribbon joist.


Step 4

Attach joist hangers to the ledger board and the ribbon joist. Align the inside edge of the joist hanger with the reference mark on the face of the board. You should be able to see the X inside the joist hanger. Once aligned, screw or nail the joist hanger to the board. Use a piece of scrap joist material to fit the joist hangers as you go.


Step 5
Set the ledger board.

If the house has wood siding, use a circular saw to cut along the chalk lines for the top and bottom of the ledger board. Make sure the blade is only set deep enough to cut through the siding.

If the house has aluminum or vinyl siding, use a fine-toothed plywood blade installed backwards to avoid chipping or tearing the siding.

For stucco or other masonry sidings, there are specialty blades available.

After the siding is cut, pry it from the wall. Use a chisel to clean up any ragged edges.



Step 6

Install Z flashing behind the siding for the entire length of the ledger board. Z flashing is standard, preformed metal flashing that fits behind the siding and over the ledger board. If the ledger is too long for one piece of flashing to cover, leave a 3-inch overlap where the pieces meet. Remember to run a thick bead of polyurethane or silicone caulk in the joint between the siding and flashing.


Step 7

Drill 3/8 inch pilot holes through the ledger board for the 3/8-inch-by-4-inch lag screws that will secure the ledger board to the house. Space the pilot holes approximately 24 inches apart. Stagger one 2 inches from the top of the ledger board and the next 2 inches from the bottom of the ledger board.


Step 8

Bolt the ledger board to the house.


Step 9

Fill the pilot holes with silicone or polyurethane caulk. Slip a fender washer over the lag bolt, and drive it until you feel the bolt take hold in the house's rim joist. Use a socket and ratchet to finish tightening the lag screw. Repeat this process until all of the lag bolts are installed.



Setting the Posts and Beam


Step 1
Post anchor

Once the concrete footings have hardened, secure the standoff post anchor (also called a metal post hanger) to the J-bolt with a nut and washer. Stand the post in the post anchor. Plumb the post with a 4-foot level. Brace the post and fasten it to the post anchor. Use a water level to mark the post where it reaches the bottom of the ledger board. Use a combination or framing square to mark the post on all four sides. Cut the post level with the bottom of the ledger board. Use a square to mark the post for the beam notch. The notch should face away from the house and be 3 inches wide and as deep as the width of the beam. To cut the beam notch, start with a circular saw and finish with a hand saw.



Step 2
Install ribbon joists.

Screw or nail the two beam boards together flush, with the crown edges facing the same direction. The screws or nails should be in rows of three, spaced approximately 24 inches apart, and driven in from alternate sides to ensure that the boards don't separate.



Step 3

Set the beam in the beam notches, and center it on the posts. Run a screw through the back of the post into the beam to hold it temporarily. Square and cut two of the joist boards to the required length. Place one of the joists in the far-left joist hanger and one in the far-right joist hanger.

Remember to put the joists in place with the crown edges up.

Lay the joists across the beam, and line them up with the reference marks on the top of the beam. Use the three-four-five method to check for square. Once the beam and joists are square, toenail the joists to the beam, and screw or nail the joists to the joist hangers on the ledger board.


Step 4

Install the ribbon joist over the ends of the two joists.


Step 5

Starting from the face of the beam, drill two offset 1/2 inch holes through each post. Use 1/2-inch-6-inch carriage bolts to secure the beam to the posts. Place the nut and washer facing the house.



Installing Intermediate Joists and Decking


Step 1
Ribbon joists and double joists.

Square and cut all the remaining joist boards to the required length.



Step 2
Cover the frame with decking.

Fasten joist boards to the outside of the left and right joists. Toenail them to the ledger board, beam and ribbon joist. Fasten the double joists together the same way you did the boards for the beam.



Step 3

Slide the next joist into the joist hangers on the ledger board and ribbon joist. Fasten each end of the joist to the joist hangers and toenail it to the beam. Continue this process until all the joists are in place.


Step 4

When you begin laying the decking, it's a good idea to lay a couple of pieces of plywood on top of the deck about 2 feet from the wall. The plywood gives you a good working platform until there's enough decking from which to work.


Step 5

Lay the decking so it runs across the joists and parallel to the house. Remember to lay the decking with the crown side up. Cut the first deck board to match the deck length. If the deck is longer than the deck boards, line up the left edge of the decking with the outside of the left joist. The right edge of the decking board should fall on the center of one the intermediate joists. Butt the decking board tightly against the house and screw or nail it in place. Put two fasteners in the decking each time it crosses a joist, about 1 inch from the edge of each deck board. Butt a second decking board against the edge of the first one. Mark the second board even with the outside of the far-right joist. Cut the second decking board and fasten it to the joists. For aesthetic purposes, stagger the joints where the decking boards meet.


Step 6

Lightly tack a 16d nail into each joist tight against the first deck board. The nails ensure even spacing between boards. Line up the left edge of the next board with the first one. Push the board tightly against the nails and fasten it to the joists. Continue this process until the entire frame is covered with decking.


Step 7

There will probably be some uneven or overhanging boards on the right side of the deck. Make a mark on the board farthest from the house just outside the far right joist. Snap a chalk line to the right edge of the first deck board. Use a circular saw to cut along the chalk line.



Installing Deck Railings


Step 1
Deck railings

The requirements for railings vary between locations. See the local building inspector for the following information:

  • Maximum distance allowed between railing posts
  • Required railing height
  • Maximum height allowed for the bottom rail
  • Maximum distance allowed between rail pickets


Step 2
Deck railings

Determine the number of railing posts you need. You'll need one for each corner where the deck butts against the house and two for each outside corner. To determine the number of intermediate posts required for each side, measure the distance between two corner posts, divide by the distance allowed between posts, round any fraction up to the next whole number and subtract one. For example, if the distance between corner posts is 9 feet and the distance allowed between posts is 5 feet:

9 / 5 = 1.8 which rounds up to 2

2 - 1 = 1 intermediate post between these corner posts

Repeat this process between each set of corner posts and add the totals to determine the total number of intermediate railing posts you need.



Step 3

The overall height of the railing is determined by local code. The building inspector can provide you with this information. For example, we'll use 36 inches from the top of the finished deck to the top of the rail. Cut 4 x 4 posts to length, overall railing height plus flooring thickness plus joist width minus cap rail thickness. In this case:

36 in. + 1 in. + 7 1/4 in. - 1 1/2 in. = 42 3/4 in.

The railing posts in this example would be cut to 42 3/4 inches.


Step 4

Install the corner posts 8 inches in from the corners. Have a helper hold the post flush with the bottom of the joist while you drill a 1/2-inch hole through the post and joist. Use a 1/2-inch-by-7-inch carriage bolt to secure the post to the joist.

Plumb the post, drill a second 1/2-inch hole through the post and joist, and use another 1/2-inch-by-7-inch carriage bolt to stabilize the post. Repeat these steps until all the corner posts are installed. Install the intermediate posts evenly spaced between the corner posts. Remember there can be less than maximum distance allowed between posts but not more.


Step 5

Install the 2 x 4 top and bottom rails. Secure the bottom rail 3 1/2 inches up from the top of the deck. Put scrap pieces of 2 x 4 blocks against each post and rest the bottom railing on top of them. Nail the bottom rail in place. Secure the top rail flush with the top of the posts. Let the top and bottom rails extend past each corner post and fasten them where they meet.


Step 6

Center the 2 x 6 cap rail over the posts and nail in place.


Step 7

Attach the pickets, (2 x 2) butted against the bottom of the cap rail and flush with the bottom of the bottom rail.


Step 8

To give the pickets a more finished look, cut the bottoms at a 45-degree angle. A miter saw speeds up this task.



Adding Stairs to Your Deck

Adding Stairs to Your Deck

Adding the stairs to your deck may be the most difficult part of the project. Patience and a calculator will help you to finish this project.


Step 1
Finished deck

For exterior stairs, a rise between 6 inches and 8 inches and a run between 10 inches and 13 inches for each step is usually acceptable. Check with your building inspector to see how local codes apply. Determine the height from the deck surface to the ground where the stairway ends (for example 28 inches). Then determine the length from the edge of the deck to the point where the stairway ends (for example 45 inches).

You have an overall rise of 28 inches and an overall run of 45 inches. Looking at the total rise (28 inches), you can determine that four steps with a 7-inch rise will equal the overall rise. To find the run for each step, divide the overall run by the number of steps. In this example:

45 / 4 = 11 1/4 in.

You have determined that each step will have a 7-inch rise and an 11 1/4-inch run.



Step 2

Place your framing square on a 2 x 12 so that the 7-inch mark on the outside of the tongue (the short side) and the 11 1/4-inch mark on the outside of the blade (the long side) are on the edge of the 2 x 12. Trace the outside of the square onto the 2 x 12. The long line is the run, and the short line is the rise.

Slide the square up the 2 x 12 until the 11 1/4-inch mark is touching the edge of the 2 x 12, where the 7-inch mark was. Line the 7-inch mark up with the edge of the board and trace the outside of the square again. Continue sliding the square up the 2 x 12 and tracing it until you have the correct number of steps plus one.


Step 3

Extend the bottom run line all the way through the 2 x 12 and cut on that line. Extend the top rise line all the way through the board and cut on that line. Cut a slice off the bottom of the stringer equal to the thickness of the stair tread. (In this example, 1 inch.)


Step 4

Put the stringer in place to ensure it fits. When the stringer is correct use it as a template to cut the second stringer. Attach the stringers to the deck with angle brackets. Cut stair treads 2 inches longer than the stair width. Attach the treads to the stringers with a 1-inch overhang on each side.