Install Headers & Blocking
Add solid backing throughout your walls now so you can securely mount cabinets, shelves, grab bars, and fixtures anywhere you need them later.
Why Blocking is Essential
Installing blocking before drywall is one of the smartest investments you can make. It costs minimal time and money now, but saves enormous headaches later. Without blocking, you're limited to mounting heavy items only at stud locations, which rarely align with your needs. Cabinets mounted to drywall alone pull out. Grab bars fail when you need them most. Handrails wobble. Blocking provides solid backing anywhere you need it, allowing flexible placement of all fixtures and supporting heavy loads safely. This is your only chance - once drywall goes up, adding blocking requires tearing out walls.
Tools & Materials Needed
Tools
Materials
Step-by-Step Guide
Plan All Blocking Locations
Walk through each room with your floor plan and identify every wall-mounted item:
Common Blocking Needs:
- •Upper cabinets (kitchen/bathroom/bar)
- •Floating shelves
- •Grab bars and handrails
- •Towel bars and toilet paper holders
More Locations:
- •Wall-mounted TVs
- •Coat hooks and racks
- •Mirrors over 20 pounds
- •Wall-mounted desks or fold-down tables
Measure and Mark Heights
Determine exact mounting heights for each type of fixture:
Cut Blocking Pieces
Measure stud spacing and cut blocking to fit snugly between studs:
- Measure the actual distance between studs (typically 14.5" for 16" o.c.)
- Cut 2x6 or 2x8 pieces to this length
- For cabinet runs, cut continuous blocking for entire wall length
- Cut pieces slightly short (1/8") for easier fitting
- Label each piece with location and height
Pro Tip: Orient blocking with the wide face out (not edge-on) to provide maximum screw-holding surface for your future mounting screws.
Install Horizontal Blocking
Secure blocking between studs with proper fastening:
- •Position blocking at the marked height, check level
- •Toenail through the blocking into studs with 16d nails (3 per side)
- •Or screw through studs into blocking ends with 3" screws (2 per side)
- •For continuous runs, stagger joints at different stud bays
- •Ensure blocking face is flush with stud edges (not recessed)
Add Cripple Studs Above Headers
Fill the space between door/window headers and the top plate:
- •Measure from top of header to bottom of top plate
- •Cut cripple studs to this height from same lumber as wall studs
- •Space cripples at 16" on center to match wall stud spacing
- •Toenail top and bottom to header and top plate
- •Cripples provide drywall backing and maintain wall strength
Document Blocking Locations
Create a detailed map so you can find blocking after drywall installation:
- Take clear photos of each wall showing all blocking locations
- Measure from floor to center of each blocking piece
- Measure horizontal distance from corners or doorways
- Draw a simple map in notebook with all measurements
- Mark blocking locations on the floor with spray paint or marker
- Consider making light pencil marks on drywall at blocking centers during install
Essential: This documentation is critical. Without it, finding your blocking behind drywall becomes guesswork. Store photos in a permanent location.
Pro Tips
- ✓Over-block rather than under-block - extra blocking costs little now but saves major hassle later
- ✓Add horizontal blocking every 4 feet on long walls for future flexibility
- ✓Use screws instead of nails for blocking - less hammering vibration and stronger connections
- ✓Install full-width blocking (wall to wall) behind where vanities and cabinets will go
- ✓For grab bars, use 2x10 blocking and extend it 6" beyond the bar ends for maximum strength
Frequently Asked Questions
What is blocking and why do I need it?▼
Blocking is horizontal lumber installed between wall studs to provide solid backing for mounting cabinets, shelves, grab bars, handrails, towel bars, and other wall-mounted fixtures. Without blocking, these items would only attach to drywall, which isn't strong enough to support weight safely. Blocking distributes loads across multiple studs and prevents fixtures from pulling out.
What size lumber should I use for blocking?▼
Use 2x6 or 2x8 lumber for most blocking applications. The wider dimension provides more surface area for mounting screws and better load distribution. For light-duty applications like towel bars, 2x4 blocking is sufficient. For heavy cabinets or grab bars, 2x8 or even 2x10 is recommended.
When should I install blocking during the framing process?▼
Install blocking after the wall framing is complete but before drywall goes up. This is your last chance to add solid backing - once drywall is installed, you can only mount to studs. Walk through each room with your plans and mark every location where something will hang on the wall. It's better to add extra blocking than to discover you need it after drywall is up.
How do I mark blocking locations so I can find them after drywall?▼
Take detailed photos of all blocking locations before drywall. Measure from floor, ceiling, and corners to create a map. Mark blocking locations on the floor near the wall (these marks stay visible). Some pros write directly on the drywall or make small dimples in the drywall surface at blocking locations during installation.