Aluminium or Wooden Frames?
Aluminium is usually the material of choice for a glasshouse, whether in natural aluminium or with a coloured powder coated finish. An attractive coloured frame may fit into the garden better, especially if the structure can be seen from the home.
An aluminium framed greenhouse will require no upkeep, and the frame itself tends to be less bulky, therefore casting very little shade on your plants.
Wood is an attractive, traditional building material and is better suited to some garden styles. However, it needs periodic upkeep.
Wooden frames tend to be bulkier than aluminium and can cast excessive shade inside the greenhouse.