How to Measure and Fit Door Frames & Architraves for a Perfect Finish

Jaeson Ibarra
How to Measure and Fit Door Frames & Architraves for a Perfect Finish

Few elements have as much visual impact as precisely matched door frames and architraves when it comes to renovating a house. For professional results, precise measuring and careful fitting are crucial, whether you're installing a new internal door, replacing worn-out frames, or producing a more upscale finish.

We'll cover everything UK homeowners need to know about measuring, installing, and finishing door frames and architraves in this comprehensive guide, including professional advice, common mistakes, and the best materials to choose for long-lasting quality.

1. Understanding Door Frames & Architraves

Before measuring or installing anything, it’s important to understand the components:

Door Frame (Lining or Casing)

The structure fixed inside the opening to support your internal door.
It ensures the door hangs straight, swings correctly, and seals neatly.

Frames include:

  1. Jambs (vertical sides)
  2. Head (horizontal top piece)
  3. Stops (where the door rests when closed)

Architraves

Architraves sit on top of the frame to conceal gaps between the wall and frame.
They also create a refined and decorative finish.

Most common UK styles include:

  1. Chamfered
  2. Ogee
  3. Torus
  4. Pencil round
  5. Square edge (modern look)

At Door Supplies Online, you’ll find frames and architraves made from:

  1. Solid oak
  2. MDF
  3. Veneered timber
  4. Pre-finished materials

2. Tools & Materials You’ll Need

You don’t need specialist equipment — just accuracy and patience.

Tools

  1. Tape measure
  2. Spirit level
  3. Carpenter’s square
  4. Saw (hand or mitre saw)
  5. Drill and screws
  6. Hammer
  7. Nail gun or pins
  8. Chisels
  9. Adhesive
  10. Spacers or packers

Materials

  1. Door lining kit or frame
  2. Architrave sets
  3. Fixing screws
  4. Wood filler
  5. Sandpaper

3. How to Measure for a New Door Frame

Accurate measurements ensure your frame fits perfectly and the door hangs correctly.

Step 1: Measure the Opening Width

Measure the structural opening, not the old frame.

Take 3 measurements:

  1. Top
  2. Middle
  3. Bottom

Use the smallest measurement as your true width.

Step 2: Measure the Height

Measure the opening's two sides from the floor to the lintel's underside.

For accuracy, use the shorter measurement.

Step 3: Measure the Depth (Wall Thickness)

Frames must match wall thickness or include suitable packers.

Common UK depths:

  1. 90mm
  2. 120mm
  3. 133mm
  4. 150mm

Step 4: Allow Clearances

Add space for:

  1. Packers (3–5mm)
  2. Finishing adjustments
  3. Floor coverings (e.g., carpet or laminate)

4. Preparing the Opening

A properly prepared opening makes installation smoother and ensures a long lifespan.

Checklist

  1. Remove old frame completely
  2. Check walls for crumble, moisture, or unevenness
  3. Clean debris and dust
  4. Ensure opening is square with a level

If walls are uneven, packers will help maintain frame alignment.

5. Step-by-Step Guide: How to Fit a Door Frame

1. Assemble the Door Lining

Most lining kits come pre-grooved.

  1. Lay out the two jambs and head
  2. Ensure correct orientation for door stops
  3. Screw or nail together at the correct angle

2. Insert the Frame into the Opening

Lift into position carefully.

  1. Use wedges or packers
  2. Ensure even gaps on both sides

3. Align the Frame

This is the most important stage.

Check:

  1. Is the head level?
  2. Are the jambs perfectly vertical?
  3. Are the corners square?

4. Fix the Frame

Use long wood screws — do not overtighten.
Check alignment after each fix.

5. Install Door Stops

The stop should match the thickness of the door with a 2–3mm clearance.

6. Seal & Finish

Use:

  1. Wood filler
  2. Sandpaper
  3. Sealant (for air-tightness)

The frame is now ready for the door.

6. Measuring for Architraves

Architraves should fit perfectly around your installed frame.

Step 1: Measure Leg Lengths

Measure from the floor up to the underside of the head architrave.

Step 2: Measure the Head Piece

Measure the full width from outer edge to outer edge of legs.

Step 3: Choose Your Joint Type

You can use:

  1. Mitre joints (45°) – traditional and most common
  2. Butt joints – more minimalist

7. Step-by-Step Guide: How to Fit Architraves

1. Cut the First Leg

Measure and mitre the top end.

2. Apply Adhesive

Depending on the material:

  1. Grab adhesive
  2. PVA
  3. Pins for reinforcement

3. Fix in Place

Use pins or nail gun.
Check alignment with a level.

4. Fit the Second Leg

Repeat measurements and cuts carefully.

5. Install the Head Piece

Mitre both ends to meet the legs neatly.

6. Fill & Finish

  1. Fill pin holes
  2. Sand lightly
  3. Apply stain, paint, or oil (if required)

8. Common Mistakes to Avoid

  1. Measuring only once (always measure twice)
  2. Ignoring wall irregularities
  3. Installing frames out of square
  4. Using incorrect screw lengths
  5. Mitre joints cut in the wrong direction
  6. Failing to leave floor clearance

9. Choosing the Right Door Frames & Architraves

At Door Supplies Online, you’ll find options to suit every interior:

Best for Traditional Homes

  1. Solid oak frames
  2. Chamfered or ogee architraves
  3. Cottage and panelled internal doors

Best for Modern Homes

  1. Square-edged MDF or oak
  2. Minimalist profiles
  3. Flush or contemporary doors

Pre-finished Options

Ideal for quick installations — no sanding, painting, or varnishing required.

10. Final Finishing Tips for a Professional Look

  1. Use caulk to fill gaps between architrave and wall
  2. Keep mitre joints tight with clamps
  3. Consider matching architraves to skirting boards
  4. Choose hardware (hinges, handles) that suits the frame style

11. When to Use a Professional Installer

A DIY-savvy homeowner can complete the installation, but professional help is advised when:

  1. Walls are uneven
  2. Installing fire door frames
  3. Fitting oversized or bespoke frames
  4. Installing multiple doors in one renovation

12. Frequently Asked Questions (FAQs)

1. What is the standard size for internal door frames in the UK?

Common widths are 826mm, 762mm, and 686mm, but bespoke options are widely available.

2. Can I fit architraves before installing the door?

Always fit the frame first, then the door, then the architraves.

3. Should architraves match the skirting boards?

Yes — matching styles create a cohesive look throughout your home.

4. Do pre-finished frames save time?

Absolutely. They come ready to install with no staining or varnishing required.

5. How do I choose the right material?

Oak offers premium quality and longevity, while MDF is cost-effective and easy to paint.

Final Thoughts

A well-fitting door frame and architrave may completely change a space, giving it a more polished, clean, and expertly completed appearance. Homeowners in the UK can produce stunning results that last for decades by taking precise measurements, choosing high-quality materials, and installing them carefully.

Check out the wide selection at Door Supplies Online, your go-to source for superior door frames, architraves, internal doors and hardware.

For more information about our interior or exterior doors or door accessories, give us a call at 01603 622261 and speak to a member of our expert team today or Email us at sales@doorsuppliesonline.co.uk. We look forward to hearing from you.