Building Your Dream Deck – Footings, framing and more

Building your dream deck requires a few skills in layout, setting footings, framing and then decking. This article can get you started down the road to a well constructed deck project. 

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Its much easier to communicate with your sub-trades when you are using the same language ! So make sure you download the Construction Terms Definition list. This document will help you not only when dealing with contractors but also at the lumber yard or hardware store.

Whenever you are ready to make your decking choices you should review or recent article on that topic here. Maybe you need some detailed help with building your stairs, we can help with that here. Or perhaps you need some suggestions and advice on railings, we have that topic covered here too - right here.

Setting the perimeter of the deck accurately and square based on your deck plan is key to correct placement of the footings or piers.

Step 1- Place a string line parallel to the house wall marking the outer edge of the deck. The stakes supporting the string line should be several feet wider than the deck width.

Step 2 - Place screw, nail or stack at house wall where the deck will start and stop (width of deck). Pull string-lines from nail perpendicular to house wall at least 2ft past the step 1 string-line.

Tip - Contractors typically install the ledger board first indicating the width of deck (Less 1.5” on each side for ring joist) and elevation of finished deck (Less 1-1/4” for deck boards). If you are planning on installing the ledger board first, read information below on how to properly prepare and mount a ledger board.

Step 3 - Measure from corner to corner adjusting the perpendicular strings placed in Step 2 until the same dimension is found. This can also be done using lumber in place of the string.

Tip - Make sure you are measuring both diagonals in the same spot.

Step 4 - Now that your deck outline is square, it is time to mark the pier locations. Typically it is a good idea to place piers 1’-0” inside the outer edge of the deck so that they are less visible and can be hidden by skirting. Your deck design will determine the distance between each pier based on the span of the beam and load the deck is designed to carry, this is all checked by the building department during permit application. You will mark your pier centers by measuring off both parallel and perpendicular string-lines.

It never seems to fail that when doing footings/piers it is either blistering hot or cold and raining. Placing piers is exhausting work but requires accuracy or you will be cursing the installer (you) throughout the rest of the job. The first foot goes well, the last foot is always painful, don’t cheat on the depth no matter what!

Using power equipment (post hole auger) is a good idea if you have several post holes to dig and hard clay soil conditions. Use caution as power diggers have caused many sprains and strains when rocks or roots are hit. Power Augers are known to be friend throwers….so make sure you don’t ask a really good friend! J

Clam diggers, pry bars and spade shovels are manual hole digging tools and work well, but require a lot of muscle and time.

The diameter of a pier is determined by the load (weight) applied as specified by code, but is typically 8”. Many municipalities require a bell to the bottom of the footing, this “bell” refers to the flare at the bottom which spread the load evenly, think of it like an elephant’s leg and foot.

The depth is to ensure the base of the footing is below the frost line and on firm bearing soil, this depth can range from 24” in the southern states, to 48” in the north and much of the populated centers in Canada. Questionable soil conditions can also vary the depth and diameter of piers.

Take caution not to over excavate, all loose soil and water has to be removed from the hole prior to calling for an inspection.

Tip - While waiting for inspection, place a piece of plywood over the hole for safety and to reduce the amount of water seeping in if it rains.

Time to pour!

Typically we use bags of ready mix concrete which has the correct proportion of cement and aggregate, all you need to do is add water and mix. A wheel barrow and a garden hoe work great to mix the concrete. The concrete bags have information written on them to help you figure out how many bags are required per pier, based on the diameter and depth! Make sure you measure the water amount accurately, it is common to just guess and all too often excessive water is used. It is also important to mix very well so that all ingredients are combined in chemical reaction.

If there are more than a 6-8 piers, consider renting a cement mixer. Cardboard pier forms come in a variety of sizes and can be cut to the length required by using a handsaw.

When a bell to the pier is required, start with a belled hole and place the form into hole. Fill the form with three to four shovels of concrete and then lift the form so concrete spills out of bottom creating the bell shape. You can also purchase preformed plastic bells that attach to the base of the round cardboard form and precision form the bell.

Tapping the side of the form with the side of hammer or piece of wood will ensure all air pockets are removed, check that the pier is standing straight, well supported and in the correct location from the parallel and perpendicular lines. Concrete should end at least 6” above finished grade and have a slight cone to the top so water can be shed effectively.

Metal brackets are embedded in the concrete and support the wooden posts, these are often referred to as a post base connector. Choose 6x6 over 4x4 whenever possible, read on to understand why!

Tip - Prior to full set up of concrete, use a string line pulled across all the post base connectors in a pier run, parallel to house wall. This ensures the post base connectors are aligned for precise post/beam connection.

No time to watch concrete dry, time to ins​​​​tall a safe ledger board!

Proper ledger board attachment is critical for your safety and the longevity of your deck.

The ledger is a structural element of the deck therefore needs to be installed directly up against the structure of the building. Siding should be removed and proper flashing installed to protect the ledger from water damage.

There are some who suggest stacks of washers or similar devices are a good idea to reduce water damage. You may reduce the likelihood of rot but structurally it is unsound and will not pass inspection.

If you are installing the ledger on masonry make sure there is a solid connection and a bead of caulk to eliminate water penetration behind ledger.

Not all Masonry is created equal or is the method of attachment!

Brick veneer, modern homes use brick veneer which is a single layer of non-structural brick that has an air space behind it. Some Building Departments require a solid connection of the ledger board through the air space to the structural wall. Typically this concern from building departments only occurs with large decks or decks being attached half way up a brick veneer wall where the weight of the deck could crush the airspace.

CMU’s (Concrete masonry units) are typically hollow although it is a common practice for mason’s to fill the top row of CMU’s with mortar during construction. If your connector does not seem to be secure you may need to open a hole and place mortar in cavity and embed the anchor. Your plan may be delayed however it is important to do this correct.

Poured concrete walls (not masonry but for this discussion) provide a solid location for good connection. If there is a layer of insulation (Styrofoam) it must be removed or solid blocking installed behind the ledger board.

Setting the height of the ledger board and in-turn the deck is important, consider accessibility, trip hazards, protection from snow build up and finally overall deck height. Dropping the deck by one step at the door could save you money by eliminating the need for expensive railings.

Prior to drilling pilot holes for the lag bolts, layout where your joists are going to sit on the ledger board and install your hangers. Lag Bolts should be staggered and be no closer than 2” from top or bottom edge or 4” from end of ledger board.

According to the International Association of Certified Home inspectors, the formula for determining ledger fasteners is fasteners in inches = 100 ÷ joist length in feet. It is a common practice to see one fastener between each joist spacing staggered top and bottom, this “common practice” is under rated, do it right and follow the 100/joist length rule.

Note: If your home is newer than 20 years old, take the time to know if the floor structure is engineered floor joist often referred to as I joists. If the house is constructed with Engineered Joists, special considerations need to be made for connecting a deck ledger, an engineer or building inspector will be able to advise specific to your situation.

Tip - Typically once the ledger is installed (level) and concrete is curing it is time to clean up 

By the next day concrete is hard but not cured enough to bump around or apply a load. While concrete continues to cure it is a good time to prepare the ground under your deck. A quality installation would be to remove all grass, grade soil away from house, lay landscape cloth and install a course stone layer.

Assuming the post base connector was already set in the concrete it is time to start putting together the beam and cutting posts. Code permits the use of 4x4 posts however for the cost, look and structural integrity 6X6 is money well spent, therefore ensure your post base connector is designed to support a 6X6 post!

The beam depth has already been specified by the building permit, Cut the beam boards to length and orient them so the crown is facing the same way on both boards.

Tip - Contractors like to ensure the rings of the tree (look at end of board) face towards each other, bark side out, this technique is to reduce cupping as lumber dries. Yes there is debate over if orienting the lumber really has an impact on reducing cupping!

It is common to use 2-1/2” galvanized nails or deck screws to attach beams. Whichever you choose to use make sure fasteners are compatible with pressure treated lumber.

Many builders use the “half depth” rule to determine the number of nails per row when nailing together a beam (yes often referred to as girders). If it is a 2x10 beam then 5nails in a row are required, 2x8 use 4 nails. The spacing between nail rows is typically 16” which is the common length of framing hammers, so use it to quickly determine spacing. Nails should be installed on both sides of beam, this is where a power nail gun or a friend with big forearms comes in handy!

After determining accurately the level height of each post it is time to start cutting the posts. Using a combination of skill saw, handsaw or sawzall, notch the top of the post to the depth and width of 2 ply beam. Predrill 2 holes through each post and beam then insert ½” carriage bolts with washers to secure in place. This application provides a solid seat to carry load and a support up the depth of the beam which makes the connection and ultimately the deck more rigid.

With ledger board to include hangers installed and beams in place it is time to start installing deck joists. Once again you must go through the deck joists, cut them to length if necessary and mark which side crown is up for uniform installation. Take your time to measure and cut each board accurately, don’t measure one board and use that as a template for all.

Once all perpendicular joists have been installed into the hangers it is time to install the rim joist. This termination joist should be at least as deep as joists but often one size deeper. The deeper Rim Joist looks nice and provides a better mounting surface for face mount railings, see railing installation in future articles by subscribing!

Many builders also block ever 4-6 feet between the first joist and Rim joist on each side of the deck, this gives additional stability to the perimeter joists and provides solid support when railings are installed.

Tip - Look around your site, if there are small pieces of lumber that will be thrown out, start installing them as joist mid span blocking. Blocking may not be required but increases stiffness of deck and reduces twisting of joists, which combined reduces nail or screw pops in the finished deck.

  Decking ready

First let’s ensure deck is square, the joist have not been nailed to the beam therefore this is the final opportunity to ensure deck is square. Using the same techniques, measure from corner to corner until deck is square. The 3-4-5 rule is really great to ensure there is no bow in joist before fixing in place. Start by measuring and marking 3’ along house wall, 4’ up the joist (from the same point the 3’ along house wall was measured) using that friend again measure between the 3 foot and 4 foot markings which should be 5’.

You can use any division of the 3-4-5 like 6-8-10, the larger the number the more accurate the results. Once the first joist is straight using the 3-4-5 you can simple measure or cut a block to set the spacing of subsequent joists before fastening.

This is also the time to make sure the deck is level, make adjustments as necessary but realize no deck is perfectly level, use a long level or a straight piece of lumber and level for best results.

Once you are happy that everything is square and level, fix by toe nailing from joist to beam, ensuring square is maintained while nailing. You can also use small angle brackets or blocks of wood as toe nailing can result in damage to joist from water penetration.

There are many types of decking products however in this project we have selected a 5/4 board which is made specifically for decking. The 1.25” thickness by 6” width and eased edges makes for a nice finish and is priced right.

If your interested in alternative decking products you can check out our article on Decking Products here. Or have a look at the products available in your area home improvement center here.

The first board applied is always on the edge farthest from the house wall and flush to the edge of the deck. If you have built your deck correctly you will fly at the deck board installation, if not you will learn for next time! L

Most decks will be too large for continued deck boards so some type of connection will need to occur. You can butt joint boards over a joist or you can lap joint boards using a 45 degree back cut. Deck boards need to at least span 4 joists for structural support and joints should be random for better appearance.

Deck screws are designed to bight into the wood so there is no need to predrill holes unless you are tight to the end and don’t want to split the deck board. Remember to purchase a screw designed for the application, in this case it can be used with Pressure treated lumber.

Starting from one end install a screw on joist centers, lining up the board as you move down length. To reduce the likelihood of cupping deck boards placing two screws at each joist is a wise investment.

Select your desired spacing anywhere from tight, knowing wood will shrink leaving gaps, or up to ¼” space. Consider using a spacing guide like a paint stir stick for consistency.

Routinely measure from last secure board to house to ensure you are approaching house equally from end to end. Small adjustments in spacing will not be seen however a large wedge for a finish board will haunt you!

Your last board may need to be ripped to size, if you have planned so well or are so lucky to have last board fit uncut….send us a picture!

  Time for the finish!

There are too many finishes for wood decks to write about in this article however her are a few tips. for more detail on deck finishes visit our article on Deck Staining here.

1. Not all wood is created equal or ready for finish at the same time. Pressure Treated green product should sit for up to 90days before applying a finish. Other products like cedar should be finished immediately.

2. Dry material is the cause of splinters and checking (cracking), good quality oil based stains acts like lotion on dry skin. Sealers are designed to protect the material from water damage they are not stains and do little to stop lumber from drying.

3. You will re-apply stain every year, just accept it!

4. Power washers are not your friend! Go ahead and use a power washer but just be careful, excessive pressure can cause damage to wood grain. 

“Topping-Out” refers to the tradition of placing a leafy branch on your finished project to pay respect to the tree dwelling spirits displaced as a result of your project. Modern “Topping out” ceremonies include flags being hung at the highest point of a building.

Pannenbier is a Dutch tradition where a flag is hung once the top of building is reached. The flag remains until the building's owner provides free beer to the workers!

The North American DIY “topping-out” tradition goes something like this:

Find a lawn chair, prop your feet up on your tool box, loosen your boots and share a cold drink with your friend! Homage to the tree dwelling spirits is a nice touch as you admire your beautiful work!

Don’t forget to send us pictures and subscribe to learn how to finish your deck with stairs and railings. If you have not done yet, click on the button below to get the Construction Terms Definitions Document.