Self Install Detailed Guide

This guide will take you through each step of replacing your old inefficient glass with a new double glazing unit.

While most people are not experienced at working with glass, it is not rocket science! A standard wooden window has a 10 mm piece of wood (beading) on the outside to hold the glass in place. This can be easily removed. Then, by sliding a knife around the inside of the frame, the silicone seal is broken and the glass can be removed. Next we clean up the frame, then insert the double glazed unit, checking it fits flat and snugly within the frame. Once you are confident the window sits properly, remove the window, apply silicon to the frame, insert the new double glazed unit, apply silicon around the window then fix a wooden beading to hold the window in place.

Here is each step in detail.

Part 1 - Removing Old Glass

removebeading

Step 1 Removing external beading

The window is normally held in place with a combination of wooden beading and hard sealant. The wooden beading can be removed using a chisel. This should be entered between the beading and the frame NOT between the beading and the glass. Gentle levering will generally get it to come off. It is recommended that you place a putty knife against the window frame to avoid damaging the frame.

Step 1A Removing the glazing sealant

If your window has a 'putty' or sealant instead of a timber bead, the approach is a little different.

A slower process, and generally a hammer and chisel is required. Avoid having the chisel directly touching the glass. The best way is to gently tap the chisel between the cement and the frame and lever it out piece by piece.

removehard
removing glazing pins

Step 2 Removing Glazing Pins/Retainers

Most windows have glazing pins or glazing diamonds holding the glass in place, as well as silicone/ sealant. These should be removed with pliers or levered out with a chisel.

Step 3 Remove the silicone sealant from the outside

Most windows are held in place using silicone sealant. Firstly, break the edge seal from the outside using a narrow bladed putty knife. This generally works well, provided the glass is not tight against the frame. If so, do not try to force the knife into the frame as it may break the glass. While it’s okay for the glass to be broken, it’s easier to clean up if not!

Cutting silicone
removing silicon from the inside

Step 4 Removing the silicone sealant on the inside

This is the slower part of the install and most likely to cause cracking of the glass. Wear safety glasses and gloves and take your time. The most critical thing is not to rush it. Normally the seal at the top of the glass will be weakest and you can push the blade in several mm and slowly ‘cut’ your way through the silicone around the frame. You may find using a knife that has been cut at 45 degrees on each side makes cutting the corner parts easier.

Step 5 Clean Up The Rebate

Remove all traces of the old silicone from the rebate, this can normally be done best by dragging a sharp chisel or scraper along the rebate. Use a brush to remove all dust and debris. You can use a hand scraper tool from Total Tools for around $60. This works extremely well but may not be necessary if you’re only installing a few windows.

Clean up rebate

Part 2 - Installing Your New IGUs

Check and Clean IGU

Step 1 Check and Clean The IGU

Often there will be small amounts of sealant on the front or rear of the window unit. This can be removed using a razor blade in a window scraper. There also may be lumps of adhesive on the edge of the unit. These can be gently shaved off using a putty knife, chisel or window scraper.

Step 2 Check The Fit

Lift the new IGU into the frame, resting it on the edge of the window sill. Use a suction cup to lift the unit and place it in the frame. If it doesn’t fit, you will need to use a chisel or router to enlarge the window frame slightly. This is normally if your windows are slightly out of square. Push on diagonally opposite corners of the glass unit to check it does not ‘rock’. This could be because there is some residual cement or silicone on the frame or the window frame has warped.

Apply Silicone

Step 3 Apply Silicone, Lift In Unit and Apply More Silicone

Apply a continuous bead of silicone on the timber rebate (see #1) - more is more in this case and you can clean it up later. It’s most important to have a continuous seal around the glass.

Fit the setting blocks and apply a continuous and generous amount of silicone to the bottom sill where the IGU will sit. Again, more is more here as this will protect the unit from water ingress.(See #2)

Lift the IGU into the frame and press against the unit around all edges.

Finally, apply a continuous bead of silicone around the corner of the IGU and frame (see #3) filling in all gaps.

Step 4 Cut & Nail External Beading

Recessed Frame (Most Fixed Windows)

Use the 12mm tri-quad, measure and cut the top and bottom sections of beading (the horizontal sections) at right angles, then cut the verticals at 45 degrees so they cover the horizontals. It looks neater and it is less likely for water to enter the joint. Ideally use a drop saw with a fine blade to cut the beading, but a mitre board works well.



Cut Beading
Nail on bead

While pressing the quad against the window, nail 20mm long brads every 150mm.

You can use a hammer and nail, but it’s a little more risky.



Flush Frame (Some Operable Windows)

Use a small hand held router to increase the rebate so the IGU sits flush to the frame. (See example)

Apply silicone per instruction above, and nail on the 30mm rounded capping. 

Tip: mitre joints can be fiddly, and require a number of cuts to get ‘just right’. Start slightly longer than you’d expect, and trim and test fit until you have the desired join.



Capping

Step 5 Remove Excess Silicone

Allow 2 - 4 hours so that the silicone starts going off - this will leave the least mess. Use a razor blade or sharp chisel to remove the larger ‘blobs’ of silicone. Then, use paper towel and methylated spirits/IPA to remove silicone at the edge or in the middle of the window. Methylated spirits will also remove any black sealant on the glass. Often you find that silicone gets onto the paper and so you get more smears as you try to clean off existing smears, so changing paper regularly is important. If the silicone has fully dried, use a razor blade to scrape it off then methylated/IPA spirits and paper.

Step 6 Paint Your Trim!

The final step is painting your trim. Use a high quality exterior grade paint and quality brush for the best results. Two coats will suffice but three is recommended for longevity.

Remember if you get stuck - we’re here to help! We can always provide you with a day’s assistance to help finish off your job.

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