How to Knock Down a Wall in Your House

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  • Open-floor plan homes are the rage these days. And why not? Not only does this interior design give your home a more expansive atmosphere, but it also eases traffic flow, allows more layout flexibility, and makes it easy for the light from outside to enter your home.

    However, opening up your home’s interior will require you to knock down a wall or two.

    The very notion makes you nervous, does it not?

    Pretty understandable.

    And yes, knocking down a wall in your home  is a messy business, so much so that you’re better off hiring the services of a professional contractor.

    With that said, there’s no harm in knocking down that wall yourself if you know what you’re doing (and if you’re able to obtain the necessary permits).

    But before you pick up that sledgehammer, there’s one important thing you need to check first:

    Is the wall you’re about to demolish a load-bearing one?

    You can’t just go knocking walls down and hope for the best. After all, you don’t want your home to come crashing down around you.

    How to determine if a wall is load-bearing

    As the term suggests, a load-bearing wall is a wall that supports a structural load. This “structural load” can be any of the following: another wall right on top of the wall you’re about to break down, the ceiling, a roof structure, and many others.

    In other words, a load-bearing wall is a wall that carries the weight of structural elements above it, starting from the roof and down to the foundation. Load-bearing walls are typically placed on top of each other.

    The point? If you destroy that wall, you’re not only compromising the structural integrity of your home, but you’re also increasing the risk of your home collapsing in on itself.

    If you’re going to bring down a load-bearing wall, you must install another structure in its place, something that’s sturdy enough to support the load it has left behind.

    Here are methods to check if the wall you’re about to knock down is load-bearing.

    Is it an exterior wall?

    Before doing anything drastic, you need to understand first how the entire structure holds together.

    Exterior walls are always load-bearing since they’re placed around the home’s perimeter, built in a way where weight is evenly distributed along the entire property’s length. Some exterior walls are not load-bearing on account of the home’s unique design, but to tell for sure, make sure that you examine the wall closely and see its position relative to the home’s structure.

    Are there any walls and other supports above it?

    A wall that has other walls, joists and other supports above it is probably load-bearing. Otherwise, the wall wouldn’t have been able to support those structures in the first place.

    Typically, a structure’s weight is transferred directly to the floor below, all the way to the foundation. If walls are built directly on top of each other, then it’s a certainty that they’re all load-bearing.  In the same vein, attics with knee-wall supports beneath the rafters are likely to be load-bearing as well.

    Is there sufficient foundation?

    A wall, by itself, is not built to support heavy loads. It needs a strong foundation to support the weight bearing down along its length.

    If the wall concerned is on the upper floor, check if there’s another wall in the same position directly on the lower floor. Does it have sufficient foundation?

    To check, go to your home’s lowest point and check for any wall or structure that connects directly into the foundation. As already stated, load-bearing walls transfer their load directly into the structure below them. This means that any structure that connects directly to the foundation is also load-bearing and therefore should not be removed.

    If the wall is located on the first floor, check if there are girders, beams, or piers in the crawl spaces underneath. If they’re there, then the wall above is most probably load-bearing.

    The wall is parallel or perpendicular to floor joists

    Spanning open spaces, floor joists are floor framing that provides support to the subfloor and wall partitions. Load-bearing walls usually run perpendicular to floor joists, allowing the entire structure to support the load from the upper floor. If the wall in question is supporting an intersection of joists from above, then that wall is most definitely a load-bearing one.

    Check out the blueprints for the house

    If you still have a copy of your home’s blueprints, then you’re in luck. This piece of architectural document has all the information needed to tell which walls are load-bearing and which ones are not. If you can’t find them anywhere, call your home’s designer or construction contractor and ask if he or she still has a copy of the blueprints. You may also ask directly if the wall you’re looking to demolish is a load-bearing one.

    Do I Need Planning Permission To Knock Down a Wall?

    Do you need to obtain a permit to knock down an interior wall in your home? That will depend on your local laws. With that said, there’s a strong possibility that you will need one, especially if you need to knock down an entire wall. However, you still need to consult an architect or a contractor even if you’re only dealing with a partial wall.

    What you need to know about permits

    As a homeowner, you must be aware of the legislation requirements as per the building code in your locality before you hire a professional. First and foremost, the designer, architect, or engineer you’re hiring has to be registered with the municipality or the state. To check if a contractor is registered or licensed, enter the name on the registration or licensure lookup in your city or state’s official website.

    If your request to have an interior wall removed is not in compliance with your state or city’s by-laws, you need to apply for a minor variance from the Committee of Adjustments or the equivalent department in your locale.

    Other considerations:

    • Demolition permits. Depending on your locale, you might be required to obtain demolition permits (on top of building permits).
    • Site plan. You’ll be required to specify your home as well as the details of your proposal.
    • Conservation authority. You will need approval if the demolition site’s near a water source.

    Submitting an application

    To apply for a building permit, you need to present the following requirements to the Building Department in your town:

    • 2-3 sets of building plans
    • 2 copies of the site plan
    • Building permit fee

    How to Remove a Load Bearing Wall and Install a Beam

    You’ve discovered that the wall you want to remove is load-bearing…  what now?

    As mentioned earlier, you can still knock down a load-bearing wall, provided that you install a load-bearing beam to carry the load in its place.

    You’ll be surprised to know that replacing a load-bearing wall with a support beam doesn’t require too many materials. It does require a lot of work, however.

    Another thing to bear in mind: A support beam can be heavy, so make sure that you ask for assistance from a friend or two.

    But before you start knocking down the wall, there are a few things you need to keep in mind.

    What’s inside the wall?

    Once it’s established that the wall in question is indeed load-bearing, don’t demolish it without verifying if there are any electrical boxes, switches, or plumbing fixtures inside it that need to be moved. Damaging a live wire, after all, can damage your electrical appliances or circuits, not to mention cause serious injuries.

    With the right methods and tools, you can locate electrical wires in walls with minimal effort. Checking for outlets and switches where your electrical appliances are connected to is a good start. Start from a convenient corner and then trace the likely pathway of the hidden wire, checking if it’s going to emerge again from the opposite side. Make sure to check the basement/lower floor, the kitchen, the dining room, etc. to see if any utilities or wires are disappearing into the wall. Look everywhere, including room corners and the ceiling.

    Since you’re planning to knock down the wall anyway, you can choose to cut a hole in the drywall with a knife to check if there are any electrical wires behind it. Take it easy with the cutting to ensure that you don’t cut into any live wires.

    If you’re still struggling to determine where the electrical wire is hidden, using a wire tracer will help you do so. With its amplifier probe and transmitter, a wire tracer can trace electrical cables that are hidden behind walls up to 10 feet or so.

    Another tool you can use to detect hidden electrical wires is a stud detector. While it can only detect hidden wires up to 3 inches behind walls, it still gets the job done if you’re patient enough to probe every inch of the wall’s dimensions.

    Word of warning: electrical wires that have very low currents can be extremely hard to detect. If you suspect there’s one behind the wall, consult a qualified electrical contractor.

    How long will it take to knock the wall down?

    The length of time it will take to demolish a wall depends on many factors, including the wall’s size, the contractor’s skill level, the amount of electrical or plumbing fixtures involved, among many others.

    Overall, the entire task will take you around 3-5 days. The task of demolishing the wall, clearing the debris, and installing a structural beam will take 2-3 days. Then you add a couple more days for painting and plastering.

    If everything goes well, you can finish the entire process in less than a week.

    How much does it cost to knock down a wall in a house?

    Again, it mostly boils down to the wall’s size. The bigger the wall, the longer it will take and the more strenuous it will be to knock it down. Large walls support heavy loads, and you have to install a support beam that is equal to the task of picking up the slack. And if you want to build a sturdy support beam, you need to buy premium materials.

    So, how much does it cost to knock down a load-bearing interior wall? The price range varies a lot, ranging between $1,000 to $3,000. The cost may reach up to $10,000 if your home is multi-level.

    If we’re dealing with heavy loads, you should install laminated veneer lumber beam, which costs between $50 to $400. Hiring a general contractor is more expensive—around $400 per day—, but it’s a huge time-saver since you don’t have to hire different specialty contractors for one project. Hiring a general contractor may even be more cost-efficient in the long run because it allows you to consolidate all the tasks involved in the project.

    To help you make a more accurate estimate, here’s a breakdown of additional costs you need to consider:

    • Building permit. Check with your local government if knocking down a load-bearing wall inside your home will require a building permit. Permits for removing an interior wall range between $1,200 to $2,000.
    • Disposal rental. Knocking down a wall is a messy job and you will need to clean it all up once it’s over. To get rid of all the debris, you may want to hire a dumpster rental, which will cost you between $120 and $530.
    • Lead paint testing. Your structure will need to be before demolition. The cost of lead paint testing ranges between $300 to $400.
    • Drywall installation. Demolishing an interior wall may leave some parts exposed, but you can patch them up with drywall, which will cost around $1.50 per square foot. Prices will depend on the material used.
    • Wallpaper removal/replacement. Installing new wallpaper will cost you between $400 to $1,100.
    • Painting. Paint jobs involving 10-foot x 12-foot rooms will cost you around $500. Some materials require multiple coatings and will cost extra.

    How to remove a load-bearing wall and install a beam

    So, once you’ve established that a wall is load-bearing, it’s time to do the dirty work. Time to smash that wall!

    But first, you need to…

    Prepare the room for demolition

    Knocking down walls can cause dust and debris to spread inside your home. To protect your home from all that dirt, do the following:

    1. Cover the following with plastic sheeting:
    • Furniture
    • Vents (to prevent dust from spreading further inside the house)
    • Windows (to prevent damage from flying debris)
    1. Cover the floor with a tarp or a sheet of plywood.
    2. Wear safety gear, including goggles, work gloves, dust mask/respirator mask,

    Time to smash that wall!

    Okay, let’s get to the fun stuff: let’s knock that wall down.

    Is the room ready? Here are the steps to smash your wall to smithereens:

    1. Mark the area that is to be demolished. Grab a utility knife and score over the marks.
    2. Grab a sledgehammer and bore a hole between studs (use a stud finder if you can’t spot them).
    3. Position the reciprocating saw (a manual saw will do if you’re more comfortable with it) into the hole and cut out a portion of drywall between studs. Then cut out the sill and remove any remaining pieces on the floor with a pry bar.
    4. If you find any insulation, remove them carefully.
    5. Perform the same steps on the drywall from the other side.
    6. Tear down or dispose of all drywall pieces and debris and take them to a dumpster. The idea here is to ensure that your work area is as clean as possible.

    Lead & Asbestos Testing

    If your home was built before 1978, chances are there are layers of lead paint underneath the wall’s coating. Destroying a wall will cause traces of lead to spread into the air as lead dust, posing serious health risks to those who are exposed to it.

    Asbestos is another hazard you want to watch out for. Back during the tail end of the 19th century, this substance was widely used in building constructions, mostly to serve as fireproofing and insulation material. It was not until during the 60s when it was discovered that exposure to asbestos is linked to heightened risks of cancers of the stomach and the lungs, which led to its banning.  Asbestos removal is not a DIY project, and must be entrusted to the care of a professional contractor.

    Patch up the floor

    Demolishing a wall will expose the subfloor where it was previously located. As such, you need to replace the old floor with a new one. Of course, you need to use the same flooring material to ensure a smooth transition between the two.

    Building a load-bearing beam

    Your next order of business is to create or buy a load-bearing beam.

    You might be surprised to know that building a support beam is the easiest part in beam installation. That said, you need to carry out the proper steps to ensure that it’s strong enough to support heavy loads.

    Here are the steps to build a load-bearing beam:

    1. Grab a tape measure and measure the length of the section where the load-bearing beam is to be installed. If you’re unsure of the appropriate dimensions, consult a .
    2. Position a sheet of plywood on a pair of sawhorses and then cut the plywood with a circular saw until you have 8-foot strips. Note that each strip must be narrower than the dimensional lumber by a fourth of an inch.
    3. Place the dimensional lumber on the sawhorses. Grab the tape measure then measure the required length, marking it with a V pointing at the saw line. Mark the lumber’s entire width with a straight line as well then cut out the lumber that will be used for the beams.
    4. Position one board on the sawhorse and set the plywood strip on the board beam. Lay down the second board on the plywood. Don’t forget to rattle the joints a bit in the support beam to ensure they’re properly aligned with the support posts.
    5. Nail the two boards together from both sides, making sure that the nails are forming an alternating V or grid-like pattern.

    The beam is now ready for installation!

    Installing the beam

    Installing a load-bearing beam can be challenging especially if the structure is long and big. Don’t carry out this procedure without any help.

    1.  Prepare the beam socket. To make room for the beam, remove the stud in the wall that’s perpendicular to the one that you just removed. To remove the stud, break apart the nearby studs with a pry bar or a chisel. With this done, saw through the nails in the gap’s opening using a circular saw or reciprocating saw. (Word of caution: take care not to cut the cables while you’re sawing through the nails. To ensure you don’t cut off the cables, use only the tips of the saw. Once you’ve cut through the nails, it will be easier to prepare the socket for the beam installation)
    2. Install a beam cradle that will hold the beam in place. Grab two pairs of 2×4 and attach them to the floor and the tie-plate with 3-inch screws.
    3. Cut notches in the adjoining walls to make room for the beam. With assistance from at least one person, lift the beam and slip it into place. Make sure it’s resting snugly on the cradles you just installed.
    4. If you’re struggling to fit the beam members in the pocket, cut more notches at the top or the bottom until they fit right below the top plates. If the beams are loose, insert shims beneath them until they’re snug tight. Press the beam members together and make sure they’re properly aligned.
    5. Once the beams are perfectly positioned, drive rows of 16D nails along their length (at least every foot or so) so that they’re tightly held together.
    6. Lastly, take out the support wall.

    The beam is already installed!

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