Fitting Architrave - Step by Step DIY Guide

Fitting architrave around doors and windows is a task any dedicated DIY-er can easily take on! It doesn't necessarily require fancy tools and, even though you need to pay attention to measures and details, it's really not a complicated job.

We've already shared with you all the secrets for installing skirting boards and window sills, so now it's time to crown your house's mouldings renovation with a handy guide to fitting architrave!


Architraves 101

Architraves are the decorative pieces of moulding around your door frames and windows. To find out more about architraves, its uses and importance, check out our architraves essentials guide.


What You'll Need

In the list below you'll find all the tools, materials and safety gear you'll need to properly install your architraves. We've included a few power tools in the list, but these can be easily replaced for this job.

Materials and tools list:

  • Side and top architraves
  • Safety gear (goggles and gloves)
  • Tape measure
  • Pencil
  • Pipe and cable detector
  • Combination square set
  • Hammer
  • Mitre box and fine blade jigsaw (if not using power tools)
  • or Mitre saw and workbench
  • Nail gun (optional)
  • Fine sandpaper
  • Putty knife
  • Wood filler
  • PVA glue
  • Paintbrush
  • Grab adhesive
  • Sealant gun
  • Lost head nails
  • Nail punch

If you are fitting architrave that's already fully finished, then skip the nails and use the grab adhesive! On the other hand, if you are working with primed architraves, you could skip the adhesive and simply fix the architrave with nails -keep in mind using both nails and adhesive on primed mouldings is the standard practice though!


Before Getting Started

Getting ready for any type of job around the house it's a must! In this particular case, before you get started you need to check there are no cables or pipes around your door frame. Grab your pipe and cable detector and scan the surface where you'll be working. This 'step 0' is fundamental, especially if you have a switch next to your door -a very common feature.

Gather all your tools, materials, wear your safety gear and, by all means, make sure the width of your architrave is matching your skirting boards!


Fitting Architrave - Step by Step

Step 1: Draw the line where the architrave will sit

Grab your combination square -you could use a ruler or tape measure to do this too- and set it to either 5 or 6 mm. Place it on the inner edge of your door jambs and mark them with your pencil all along. Do the same with the top inner edge of your door frame. Then connect the lines. 

You'll end up with a whole inner line encompassing your door frame, 6 mm from the inside out. Double-check the line is running parallel all along!

It's standard practice to draw the line where your architrave will be positioned at 5 or 6 mm as this allows room for the door hinges. 


Step 2: Mark the architrave to fit the height and width of the door frame

Place the architrave on the door jamb and with your pencil mark where the vertical and horizontal lines you drew on step 1 meet. This is where your side architrave will meet your top architrave.

It's paramount to get the height right as this is where the different pieces of the architrave will intersect.

Do the same with your top architrave.


Step 3: Draw a 45-degree angled line

With your architrave still sitting on your door frame, set your combination square to a 45º degree angle. Draw a line joining the mark you drew on step 2, with the outer edge of the architrave.

This diagonal line is where you'll cut your pieces of architrave to create the mitre joints that will hold all three sections together.


Step 4: Mitre cuts

If you don't have a mitre saw at hand, just use a saw -make sure it's a fine tooth saw- and a mitre box. Place the pieces or architrave on either and proceed to create your mitre cuts.

Make sure you are cutting in opposite angles, in an ascending direction from the inner edges marks, toward the outer edges -for your side architrave. 

Your head architrave should also end up with opposite angles -narrow on the bottom edge and wider on the top edge.

Before sanding, make sure all three sections of architrave fit correctly.


Step 5: Sanding your mitre cuts

Sand the side surfaces of your mitre cuts until smooth and uniform. Clean the dust from the cut as you'll need a clean surface to apply the grab adhesive.


Step 6: Applying the grab adhesive to the top architrave

Now that all the sections of your architraves are cut and ready to be fitted, place your grab adhesive on the sealant gun and apply it on the back of your top architrave.  

Do so in linear movements going from side to side -stay clear from the edges, at least 30mm! You don't want excess adhesive spreading all over. Whatever you do, make sure to follow the manufacturer's instructions.


Step 7: Fitting the top architrave

You made it almost to the end! Start by placing the top architrave exactly on the marked line. Then, soak your paintbrush in a little bit of PVA glue and apply it on the side of your top architrave -on the surface that will meet the vertical architrave.

If you want to keep your head architrave in position, use about 3 lost head nails to fix the piece to the wall -this is optional! At the end of the day, a good grab adhesive can even replace nails.


Step 8: Double-checking vertical architraves length

Check one more time that the height of your side architraves matches and fit perfectly the mitre cuts of your top architrave. It's better to be 100% sure before getting into the adhesive! 


Step 9: Applying adhesive to your upright architraves

Just as in step 6, apply the grab adhesive following the manufacturer's guidelines.


Step 10: Fitting upright architraves

Fit the vertical sections of the architrave to sit nicely underneath your top architrave. 


Step 11: Nailing architrave

It will be up to you if you'd rather nail your architrave to the wall, or if you are happy using the adhesive only. Keep in mind that nailing will also add a little bit of work. At the same time, nails will give you 100% certainty that your mouldings will stay in place.

If you go for nailing, then do so using lost head nails and spread them out evenly along the architrave. Use a nail punch to settle the nails under the architrave's surface. Finish it off with wood filler -remember to let it dry and sand the surface before painting!


Fitting architrave around windows

To install architraves around your windows, simply follow the same steps, but remember to mirror the angles of each section of architraves to get the mitre joints right!

If you need more information or advice on how to choose the appropriate architraves for your home, just contact our team by emailing or calling 0800 048 0786.