How to Fit Architrave Around Doors: Perfect Mitre Joints

The Finishing Touch That Shows Your Skill

Architrave is what makes a door opening look finished. Get it right and it looks professional. Get it wrong - gaps, uneven reveals, poor mitres - and everyone notices. Here's how to do it properly.

Understanding Architrave

What it does:

• Covers the gap between door lining and wall
• Creates a finished frame around the door
• Protects edges from damage

Profiles:

• Ogee - classic curved profile
• Torus - rounded profile
• Square/pencil round - modern, simple
• Match existing architrave in the property

Planning the Reveal

The reveal is the margin between architrave and door lining edge:

• Typically 5-10mm
• Must be consistent around entire frame
• Mark the reveal line before cutting anything
• Use a reveal gauge or combination square set to your measurement

Tools Needed

• Mitre saw (power or hand)
• Nail gun or hammer and panel pins
• Tape measure
• Combination square
• Pencil
• Coping saw (for internal corners)
• Pin punch and nail set
• Wood filler

Measuring and Cutting

Method 1: Measure to short point

1. Mark reveal line on door lining
2. Measure from floor to reveal line for legs
3. Add mitre allowance (width of architrave at 45°)
4. Measure between reveal lines at top for head
5. Add both mitre allowances

Method 2: Mark in place (more accurate)

1. Hold piece in position against reveal line
2. Mark the mitre point directly from the adjacent piece's reveal line
3. More accurate than measuring

Cutting Perfect Mitres

Power mitre saw:

• Check saw is calibrated to true 45°
• Support the full length of architrave
• Cut on the waste side of the line
• Let the blade stop before lifting

Mitre box (hand):

• Secure architrave firmly
• Use sharp, fine-toothed saw
• Long, smooth strokes
• Don't force the blade

Tips for tight mitres:

• Slightly back-cut the mitre (angle the back edge back slightly)
• This ensures the face edges meet tightly
• Test fit before nailing

Fitting Sequence

1. Fit head piece first
   • Position on reveal line
   • Check level
   • Pin in place (not fully driven yet)
2. Fit first leg
   • Offer up to head piece
   • Check mitre joint
   • Adjust if needed
   • Pin in place
3. Fit second leg
   • Same process
   • Check both mitres close tightly
4. Final fix
   • Drive pins home
   • Set below surface with punch
   • Pin through mitre to lock joint

Dealing with Problems

Gaps in mitre:

• Small gaps - fill and sand
• Larger gaps - recut if possible
• Can sometimes close gap by adjusting position slightly

Walls not square:

• Scribe back of architrave to wall
• May need to adjust mitre angle slightly
• Decorators caulk fills small gaps to wall

Door lining not plumb:

• Architrave follows the lining, not the wall
• Keep reveal consistent, even if lining is off

Fixing Methods

Nail gun (fastest):

• 18 gauge brad nails typical
• 32-40mm length
• Pin into lining and wall

Panel pins (traditional):

• 40mm pins
• Pre-drill in hardwood
• Punch below surface

Adhesive:

• Grab adhesive plus pins
• Good for MDF architrave
• Reduces pin holes to fill

Finishing

1. Fill all pin holes with appropriate filler
2. Fill any gaps in mitres
3. Sand smooth when dry
4. Caulk gap between architrave and wall
5. Prime bare wood if painting

The Bottom Line

Good architrave fitting shows attention to detail. Consistent reveals, tight mitres, and careful nailing make the difference. Take time on the first piece - if that's right, the rest follows. A good mitre saw and nail gun make the job much faster, but skill matters more than tools.