Designing Your Conservatory

There are three possible frame materials to choose from when designing your conservatory - architectural aluminium, timber or uPVC. At David Fennings we deal solely in architectural aluminium and timber, as we consider these materials far superior to uPVC.

Advantages of Architectural Aluminium Conservatories

Modern architectural aluminium conservatories have virtually nothing in common with the cheap aluminium conservatories of the 1970s. Various quality improvements, such as the introduction of thermal barriers and the computerisation of manufacturing, have meant that it is now possible to purchase outstandingly high quality designs, which are many times stronger than uPVC and sturdy enough to accept a glass (rather than polycarbonate) roof, at prices which can be competitive with uPVC alternatives.

Architectural aluminium systems are now extensively used on mainland Europe and for most commercial glazing.

Architectural aluminium allows slim, strong, rigid frames, will not warp, twist or rust and does not need reinforcing. The architectural aluminium alloy used for glazing systems has a strength approaching that of mild steel, and is more than 20 times stronger than uPVC. The amount of expansion and contraction in architectural aluminium is only one third of that in uPVC, giving greater structural stability.

Aluminium has a melting point of 660°C - an important security feature, as it cannot be melted with a blow torch by someone attempting to break in - unlike uPVC which has a distortion point of just 80°C. Aluminium does not contain chlorine, unlike uPVC which gives off toxic dioxin fumes when it smoulders (100°C) or burns.

Architectural aluminium is maintenance free. It does not attract dirt electrostatically, unlike uPVC, and it doesn't need annual maintenance. Architectural aluminium buildings are finished with a polyester powder coating to BS6496, which is scratch and chip resistant.

Architectural aluminium can incorporate any type of glazing, and in particular glass sealed units 24mm thick.

Manufacturers of aluminium conservatories will usually provide a 10 year guarantee or similar.

Advantages of Timber Conservatories

Timber conservatories supplied by David Fennings are rapidly becoming recognised as having achieved an unequalled standard of individual quality.

Our designs are manufactured using high precision computer-controlled machinery operated by skilled craftsmen. Selected hardwoods are chosen for their strength and durability before being moulded into the unique profiles requested by many of our customers to provide their individual requirements or harmonize with existing windows.

Most of the timber conservatories we supply are bespoke. There are, however, some standard sizes for simpler designs and to accommodate smaller budgets.

Finish: The timber is given a high penetration base coating using total tank immersion, before finishing with a microsporous stain or paint. This treatment guarantees that no flaking or peeling ever occurs, ultraviolet fading is minimised and further maintenance is usually limited to a single coat application after a 3-4 year period.

Timber is an environmentally-friendly, renewable building material. All our timber comes from managed plantations which will be replanted. Growing trees absorb CO2 (the greenhouse gas) from the air. Processing timber uses only 10% of the energy required to process synthetic alternatives.

Disadvantages of uPVC Conservatories

uPVC conservatories are generally made of uPVC windows bolted together, with a 'kit' conservatory roof.

These windows were originally intended for fitting into openings, and not constructing buildings. Because of this, uPVC designs usually have steel "stiffening" within. This is sometimes called "reinforcement", but this is not strictly true as it stops short of the corners. uPVC when used for load bearing structural members is prone to cracking, particularly at the welded corners.

Because uPVC conservatories are much weaker than architectural aluminium conservatories, they may be unable to support the weight of a glass roof, forcing you to choose polycarbonate. Although this material is used extensively, it has many disadvantages - see Designing Your Conservatory: Roof - Glass or Polycarbonate? for more information.

uPVC windows degrade rapidly, losing their white or brown colour relatively quickly. The rubber gaskets shrink and let in water; the double glazing loses its seal and steams up often, well under the expected life span of ten years, and the so-called stainless steel mechanisms start to rust.

Because uPVC windows can be produced cheaply and easily, anyone can set up in business as a uPVC conservatory manufacturer. It does not take a great deal of engineering knowledge, technical ability or manufacturing skill to produce a uPVC conservatory, and the machines required can be purchased for just a few thousand pounds. This has led to hundreds of small companies starting up, and often going bust within a few years - sometimes starting up again under a different name. When purchasing such a high value item, the buyer should be sure that their supplier is a reputable firm.