The frame is the part of a conservatory you look at, the part that decides how much glass you get for the opening, and the part with the widest price range. Four materials dominate in Britain and each is genuinely better at something, which is why all four are still sold.
The uPVC or plastic conservatory, and what the volume product does well
UPVC is the cheapest, needs almost no maintenance, and performs well thermally for the money. Its weakness at conservatory scale is section width: the frames are thicker than aluminium or a good timber, and across a run of large glazed bays that shows. Colour options beyond white cost extra and, on foiled finishes, the long term appearance depends on the quality of the foil. On a modern estate house it is frequently the sensible answer.
Wooden conservatories: softwood, hardwood and engineered timber
Timber gives the finest sightlines for a traditional building and can be painted any colour and repainted later, which no plastic can. Modern conservatory timber is usually engineered, laminated from sections so it is more stable than solid timber and less prone to twisting. Hardwood costs more and lasts longer in exposure. All of it needs a maintenance cycle, which is the real commitment: a timber conservatory that is repainted on schedule outlives most alternatives, and one that is not does not.
Oak framing is a different kind of building
A green oak framed conservatory is structural carpentry rather than an infill frame with glass in it: heavy posts and beams carrying the roof, with glazing set between them. It suits period and rural houses, it is the most expensive option by a distance, and it moves as the oak seasons, which is expected and is designed for rather than a defect. It is a specialist trade and not something a general conservatory installer will do.
Aluminium, and why contemporary designs use it
Aluminium is strong, so the frames are slim and the spans can be long, which is why large contemporary conservatories and most lanterns use it. A thermal break inside the section does the insulating work the metal cannot. It is more expensive than UPVC and it holds a powder coated colour indefinitely. Where the aim is maximum glass and minimum frame, it is the only material that gets there.
Choosing, without the showroom
Match the house first: a Victorian terrace is a timber or slim aluminium problem, a 1980s estate house is a UPVC one, a barn conversion is oak. Then look at the sightlines in the flesh rather than in a render, because section width is the difference you will notice every day. Then ask what the maintenance cycle is and cost it honestly over twenty years, because that is where timber and plastic genuinely diverge.
Questions people ask about timber conservatory
Is a timber framed conservatory high maintenance?
It needs a repainting or re-oiling cycle that UPVC and aluminium do not. Kept to that cycle it lasts extremely well; neglected, it deteriorates faster than the alternatives.
Is hardwood worth the extra over softwood for a timber frame conservatory?
In an exposed position and on a building you intend to keep, generally yes, because it resists decay better and holds a finish longer. Engineered softwood is a real advance on plain solid timber and is a reasonable middle option.
Does an oak framed conservatory move?
Green oak shrinks and checks as it seasons, and that is expected. A competent oak framer designs the joints and the glazing details around it, so it is a characteristic rather than a fault.
Which material gives the most glass?
Aluminium, by a clear margin, because it is strong enough for slim sections and long spans. UPVC gives the least for the same opening.