How to Install a Beam to Replace a Load-bearing Wall

Home Improvement: With a little planning and research someone with reasonable carpentry skills should be able to remove a load bearing wall and replace it with a beam. Regardless of the size of opening you want, the process is very similar.

How to Install a Beam to Replace a Load-bearing Wall

How to Install a Beam to Replace a Load-bearing Wall



Photos by Ron North; Lead photo by Supermatros | Dreamstime.com

As you sit there sipping your morning coffee you decide it has got to go. That wall. That pesky divider between the kitchen and living room. You've been thinking about it for years, and now you're finally going to tackle this project. It's doable for a reasonably talented woodworker or DIY'er. There are however some important aspects to be aware of.
 
This article uses information from the 2018 BC Building Code, which is available online for free. It's based on the 2015 National Building Code, which is widely adopted across Canada. Local conditions such as the snow load need to be considered. A building permit would generally be required for this renovation, so it would be wise to talk with your local building official when planning the project.
 

Load bearing?

Firstly, is it a load bearing wall? If not, it could save a tremendous amount of work and cost. The age of the house should give some clues. Roughly speaking, if the home was constructed during the 1960s or before, it was likely “stick framed”. If so, it means many of the interior walls, parallel to the roof ridge carry some load. Possibly just ceiling joists but also an actual roof load may be supported by the wall(s) in question. A home built in the 70s and beyond often employs manufactured trusses that typically span from outside wall to outside wall, meaning there would be few if any interior load bearing walls. Note, that if the wall is supporting a floor, there would be the load from that floor but also any additional loads imposed by possible roof loads.
 
Now that you've determined the wall you want to remove is load bearing, for simplicity, let’s assume the wall is supporting a roof load only. You will need to decide on the type and size of beam to support the load. The span of the opening will have the greatest impact on beam selection.
 
In general, built up beams using lumber could work for spans up to about 4-5 meters (13'-16'). See building code span tables. Steel beams can span considerably farther. However, there is only one span table in the code and that is for the support of floors. If the specified snow load in your area is not greater than the floor load (1.9 kPa or 40 psf) then a beam could be selected from the span table. If the snow load is greater, then an engineer will be required to size the beam.
 
Another possibility is Laminated Veneer Lumber (LVL). There are no span tables in the building code for these so an engineer will be required. Typically, the manufacturer will provide the engineering for the beam. This would be for a simply supported beam with no point loads or other complicating factor. Otherwise an engineer would be required to size the beam, and possibly its support.
 
There are other beam types such as Glu-Lam, Parallam or a girder truss. I have not included these as they are not typically used in this type of alteration. 
 
There are advantages and disadvantages to each type of beam;
 

Built up lumber beam

Pros
  • Likely the cheapest. (2x12x16 SPF approximately $34)
  • Convenient, bought off the shelf at a lumber store.
  • Engineering not required. Use the span tables in the building code.
Cons
  • Limited on the maximum span.
  • Sometimes the materials are inconsistent.
  • All lengths may not be available.

Steel beam

Pros
  • Moderate cost. Approximately $10 per foot (W150x22, W6X14)
  • Long spans possible, within the limits of the span table.
  • Low profile, relative to the span. (Could be important if trying to hide the beam in a floor).
Cons
  • Requires lumber bolted to the beam so joist hangers can be installed. If the beam is to be exposed (hang below the floor or ceiling) it would still require lumber added to act as a nailer for the installation of the final finish.
  • Heavy. Even the smallest beam is 22 kgs per meter (15 lbs per foot). A 6 meter beam would weigh 135 kgs. At least three or four people will be needed to place the beam.

Laminated Veneer Lumber (LVL)

Pros
  • Long spans possible.
  • Lighter, easier to install. Multiple plys can be installed separately.
  • Engineering usually done by the manufacturer, supplier.
Cons
  • The most expensive option. Approximately $11 per foot per ply (1.75 inch X 14 inch).
install-beam-thick-plywood
Think Thick Plywood – Laminated Veneer Lumber (LVL) is essentially very thick plywood manufactured in a variety of dimensions.

install-beam-illo

Time for an example

We will make some assumptions for our example project. The opening in the wall we want is to be 16' (4.8 metres). The width of the building is 20' (6 metres) and the specified roof load is 30 lbs/sq ft (1.5 kPa).

The Specified Snow Load (SSL) is calculated using the ground snow load and the rain load for the location of the building. E.g. the ground snow load is 2.1 kPa. The rain load is .3 kPa. The roof factor is .55. Therefore, the SSL is [2.1 X .55] +.3= 1.45kPa. (30.4 lbs/sq ft).

The span tables, no matter what type of beam you choose, are all similar. Just use the SSL, the type of beam (sawn lumber or steel) and check the maximum allowable span.

For our example, we'll start with a built up wood beam to see if that works. It can be seen from the span table that the largest span possible under the 1.5 kPa specified snow load would be 4.18 metres (13.7 ft). Therefore, a built-up wood beam won’t work in this case.
 
Next check a steel beam. The table below, 9.23.4.3. is typically used for floor beams. However, since the assumed floor load of 40 lbs/sq ft (1.9kPa) is actually more than the specified roof load applicable to our project, the table can be used to select a beam. From the table we can see a W150 X 22 beam will span 5.2 meters (17.06 ft). Therefore, we could use a steel beam to span the 16' opening.
 
We know an LVL beam will be able to span the 16' opening because the manufacturers’ engineer will design a beam specifically for the project. It was decided to use the LVL because it will be easier to install. Two people can carry and lift each piece of the three-member beam into place. The steel beam, while cheaper, would be harder to handle, even with assistance. Typically, the beam will be manufactured 150mm (6") longer than the span to allow for a minimum bearing surface of 75mm on each end. The beams are made (and priced) on 600mm (2') increments, so the beam will be 5.5 metres (18') long and cut on site. 
 

Getting to work

Temporary walls are constructed on both sides of the existing wall that is to be removed. Build the walls using stud spacing the same as the spacing for the supported roof rafters and ceiling joists. A single top and bottom plate is sufficient.

install-beam-temporary-walls
Add Two Temporary Walls – Temporary walls in place on either side of the existing load bearing wall supporting the ceiling joists and roof rafters.

Now the existing wall can be removed and the joist cut to accommodate the new beam. Cut the joists such that the beam will be centered on the ends of the existing wall. (Depending on the width of the new beam, the wall may need to be widened at the bearing points by adding studs to the side of the existing wall.) The individual pieces of the LVL can now be installed.

install-beam-position
Position the New Beam – The first ply of the LVL is in place above where the now removed bearing wall was located. Each ply is about 56 kgs (123 lbs) so it is manageable for two people.
 
The remaining two plys of the LVL are installed (nailed or bolted, as required by the engineered detail) and hangers nailed in place. The temporary walls can then be removed.

install-beam-secure
Secure it in Place – The installed LVL beam. In this case each ply is nailed to the next. Some designs may require the pieces of the beam to be bolted together.
 

Points to remember

  • Get the building permit that indicates the specifications for the beam you have chosen before ordering the beam.
  • Take your time with the construction of the temporary wall. Double check you have everything supported properly.
  • Confirm the walls/foundations below are aligned correctly to support the new point loads at each end of the new beam. Plumb a line down from the center of the bearing for the beam on to the floor. Drill a hole through the floor, and then see below where the hole is in relation to the walls/foundations.
  • The space between flooring and the walls below must have solid blocking installed to transfer the load to the wall below. The blocking (and the studs in the wall below) must be as wide and as long as the bearing point above.
  • The individual pieces of the LVL may need to be clamped temporarily to ensure they are tight to each other before nailing. Clamping may not be required if they are to be bolted.
  • Nails (or screws) specifically designed for hangers must be used. Standard nails and screws likely won’t have the sheer strength to meet the design specifications for the hangers. 
With a little planning and research a person with reasonable carpentry skills should be able to accomplish this alteration. Regardless of the size of opening you want, the process is virtually the same. Support the floor or roof, install the appropriate beam with adequate bearing and then remove the temporary walls. If you want to tackle the install, most building inspectors will be happy to help with advice.      

install-beam-tables


 
RON NORTH
ron-north

ronor@shaw.ca
Ron North has been involved in the construction field for over 50 years, most as a building official. Good heavens retire already! His book “Building Inspector Memories” tells tales of some not so successful renovations.
 

 


 

 

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