Use Of Aluminium For Windows and Doors

Aluminium - A Very Useful Material

Aluminium is a very useful metal. It is light, strong, easy to form and machine, low cost and, by anodising the surface, can be made corrosion resistant and is very plentiful. Aluminium is the third most abundant element in the Earth's crust after oxygen and silica.

It is made by smelting bauxite at very high temperatures in electrically powered smelters which use very large amounts of power.

Aliminium is replacing other materials for all sorts of uses particularly in the building industry. Aluminium has certainly revolutionised aircraft. At the start of the second world war we had biplanes made from plywood, canvas and string but by the end of the war, a mere five years later we had monoplanes made from aluminium.

Advantages of Aluminium

So what is all the fuss about? Well, as the aircraft industry proves, aluminium it is a very useful metal. It is light in weight, it is soft and malleable making it easy to form, machine and extrude but is rigid enough to be used for lightweight structural purposes such as aeroplane frames (as long as its use is correctly designed). It also resists corrosion (sorry that’s not true) in fact it corrodes quickly forming a dense layer of oxide (aluminium rust if you will) on its surface which protects the metal underneath from further corrosion. This makes it a little tricky to weld but with modern welding techniques (mig and tig) this is easily overcome.

It also conducts heat and electricity very well and so it is being increasingly used to replace copper for pipes and electrical wiring though while it is not as effective as copper, it is far, far cheaper.

On top of all this aluminium is cheap, it is after all the most common element on our planet after oxygen and silicon. It does have a couple of downsides in that it is soft so paint doesn’t stick to it very well and, owing to its high melting point (2,000 degrees C), smelting it takes a lot of electrical energy.

Anodised surface treatment for strength and colour

Aluminium is usually supplied “anodised”. Anodising is an electrical treatment which increases the amount of aluminium oxide (corrosion) on its surface. This oxide layer provides a hard, wear resistant surface that protects the metal underneath from further corrosion and also provides a surface roughness which makes it easier to paint. Anodising also makes the surface porous so it can be stained in a useful range of colours such as black, bronze, blue, gold, red, yellow, etc.

A Wide Range of Extruded Sections

Aluminium is supplied in a range of very useful extruded sections ranging from simple round tubes to complex sections used for specialist purposes such as curtain rails, car roof racks and artificial insemination equipment for giraffes. It is also used, of course, to makes those clothes racks that inevitably fall apart as you are just placing the last wet sock of a full load of washing on them. And here we come to why it is being used to make frames for windows and doors.

Window and Door Frames

When we make window and door frames from wood we have to cut grooves and slots in the wood to hold the glass or form a draft seals, these slots and grooves are costly and wasteful. A well designed aluminium section has these slots already formed plus additional slots for hidden screws, rubber sealing strips or felt draft excluders.

Low Maintenance

The final benefit is a big one - very low maintenance. It never meeds to be rubbed back and repainted, it won’t rot in the rain and, unlike wood, it won’t swell as it gets wet or twist and warp as it dries out.

Things to watch for when using Aluminium for Windows and doors.

In Indonesia windows and doors are very rarely made to standard sizes and so aluminium frames are usually tailor made on site. The results can be variable depending on the skills of the people making them.

It is important to make sure that they are assembled correctly.

With unusual shapes and no written instructions you may find that the people assembling your windows and doors don’t know how they are meant to go together. I recently came across dozens of doors made for a large project that had been assembled by 3 different crews, they had all used different methods but in fact none were assembled correctly.

Another thing to watch for is that they are waterproof. A case of severe water damage to a wall on a building in Serangan was traced back to rain beating against an exposed wall getting into aluminium window frames through the corner joints and from there into the structure of the batako wall. It all goes down to the design of the frames and the method and accuracy of manufacture. Silicone may be used to seal up the window frames but it doesn’t stick very well. Sikaflex is much better.

Well designed window frames are self draining, they collect water that penetrates and allow it to drain out in a controlled manner.

Aluminium Windows and Doors - A Checklist

Things to check for in the construction of aluminium window and door frames are:

1. Properly constructed, this is particularly important if the door has louvres or “plank” panels.

2. Good fit of window and door frames into the walls and with effective corrosion resistant screws.

3. Effective hinges that won’t rust.

4. Good fit of the window into its frame with effective rubber seals.

5. Accurate corner joints.

6. Effective way of replacing broken glass.

7. Doors and windows should not catch their frames.

8. Doors should not catch the floor.

9. Locks and catches all working correctly (lever catches are better than the lift up ones).

10. Inspect for dents and scratches and ask the installer to replace poor quality work.

It is a very good idea to find a reputable specialist contractor who guarantees his work (did I say guarantee? Some people do provide them you know).

For me personally aluminium is a very poor substitute for the aesthetic beauty if natural wood but the trees are rapidly running out, to say nothing of the loss of our natural environment, and so aluminium presents a very viable and useful option.