Block walls are attachment points between wall studs that provide support for cabinets, shelves, or other heavy fixtures. Without blocking, cabinets can become loose, damage your walls, and even injure passersby. Read how to block behind walls for cabinets and fixtures in our step-by-step guide below, and watch the video above for tips from This Old House expert Tom Silva.
Why Blocking Behind Walls is Necessary
Mounted fixtures and cabinets can loosen over time if you don’t have adequate blocking behind your walls. This could damage your walls and even injure passersby in your home. Below are a few reasons contractors use blocking behind walls:
- Create support for heavy fixtures to prevent sagging
- Enhance overall stability of wall-mounted elements
- Minimize wall damage from items that don’t have proper support
- Provide fixed attachment points for cabinets so they don’t move
When to Install Blocking
Below are the points at which you should install blocking:
- Before you install kitchen or bathroom cabinets
- Before you mount heavy fixtures, such as televisions or shelving units
- During new construction or gut renovations
- When you’re planning to add grab bars or other safety features
Materials and Tools Needed for Blocking
Collect the items below before you start the blocking process:
- Drill and screws
- Level
- Lumber
- Measuring tape
- Pencil
- Safety glasses
- Saw
- Work gloves
Step-by-Step Blocking Process
Follow the steps below to install blocking between wall studs:
- Measure and mark: Use your cabinet plans to figure out where to place the blocks. Measure and mark your wall.
- Cut the lumber: Measure the distance between studs before making cuts.
- Position the blocking: Place the cut lumber horizontally between the heights you marked.
- Secure the blocking: Use screws to attach the blocking to the sides of the studs.
- Check for level: Confirm that the blocking is horizontal and level before you permanently attach it.
- Repeat as necessary: Install additional blocking as necessary.
Aim to measure low on the wall where stock is least likely to distort.
Tips for Effective Blocking
Follow the tips below to create a solid foundation for the wall-mounted items in your home:
- Add extra blocking for particularly heavy items to reinforce support.
- Consult local building codes so that you meet all of your municipality’s requirements.
- Install blocking at different heights to accommodate different types of fixtures.
- Use lumber that matches the thickness of the studs.
Common Blocking Mistakes to Avoid
Even the most skilled contractor can make mistakes. Below are common issues you might encounter and tips on how to fix them.
- Misalignment issues: Carefully align your blocking with your fixture attachment points.
- Neglecting to level: Always make sure blocking is level.
- Overlooking existing utilities: Be conscious of the locations of electrical and plumbing fixtures to avoid complications.
Professional vs. DIY Block Wall Installation
Many homeowners can tackle this project by themselves, but certain situations call for professional services. Contact a pro if any of the following apply:
- You have multiple fixtures that are complex.
- You have an older home that might need expert handling.
- You have load-bearing walls that a professional should handle.
- You need to make extensive modifications and adjustments to existing walls.
