Garden rooms are sold by style and built by material, and the two are not the same decision. What the market calls an aluminium garden room is nearly always a timber frame with aluminium on the outside, so the first thing worth establishing about any quote is whether the material named is the frame, the cladding or the windows. Once that is clear, three choices decide what the building looks like in ten years and what it asks of you to keep it that way.
What an aluminium garden room is underneath
A softwood or engineered timber frame is the standard build at this size, because it is cheap, easy to insulate between and simple for any joiner to work with. Structural insulated panels are the upgrade and masonry is a different kind of building with a different foundation under it. Aluminium appears as cladding, as window and door frames, or as both, and very rarely as the structure. A quote that names a material without saying which of the three it means has not told you anything yet, and that is the first question to ask.
Cladding is the decision you will look at every day
Cedar and larch are the traditional choices and they silver over a few years unless they are oiled, which is either the point or the problem depending on who you ask. Thermally modified timber holds its colour longer and costs more. Composite and aluminium cladding do not move, do not need oiling and read as contemporary rather than traditional, which is the real difference between a wood garden room and a modern one. uPVC is cheapest and is the one most likely to date the building. None of these is wrong, and the price difference between them is largely maintenance you either do yourself or pay for later.
Windows and doors are where the specification usually slips
The glazing is often the largest single line in a garden room quote and the easiest to quietly downgrade. Aluminium frames are slim and strong and suit large openings, timber suits a traditional building and needs finishing, and uPVC is the cheapest and the heaviest in appearance. Ask what the glass itself is doing as well: double or triple, what coating, and whether there is solar control, because a garden room with a lot of south facing glass and none of that is a room you cannot use in July.
Traditional or contemporary is a shape question, not a material one
What makes a garden room read as traditional is a pitched roof, smaller windows and a horizontal cladding board; what makes it read contemporary is a flat or shallow roof, large unbroken glazing and a flush material. Either look can be built in almost any of the materials above, which is why comparing a traditional quote with a modern one on price alone tells you very little. Decide the shape and the glazing first, choose the cladding that gives you the look, and compare after that.
Questions people ask about aluminium garden rooms
Are aluminium garden rooms actually made of aluminium?
Usually only on the outside. The frame underneath is almost always timber, and the aluminium is cladding, window frames, or both. It is worth asking which, because the word on the brochure and the thing holding the building up are frequently different.
What is the best material for a garden room?
There is no single best one. A timber frame with cedar or larch cladding is the common default and needs oiling to keep its colour; composite or aluminium cladding costs more up front and asks nothing of you afterwards. The right answer depends on how much maintenance you are willing to do rather than on which material is better.
Do wooden garden rooms need a lot of maintenance?
Cedar and larch need oiling every few years if you want them to keep their colour, and nothing at all if you are content for them to silver. Painted timber needs repainting on a cycle. Thermally modified timber and composite boards sit between the two and cost more to begin with.
Does the material change whether I need planning permission?
No. Permission for a garden room turns on size, height and where it sits in the garden, not on what it is made of. What the material can change is the building regulations position when the room is very close to a boundary, where fire spread matters and a combustible cladding can be the thing that has to change.