House extension: fenestration specifications on plan

House extension: fenestration specifications on plan. Fenestration in architecture is concerned with the provision of windows and doors in a building. Of all the technical design features that make up the working drawings, getting the fenestrations specifications right is perhaps the most critical. The threshold between what is a good choice and bad is perilously slippery, so proceed with care.

Before we go into the types of fenestration that you will likely come across, let’s look at four over-arching factors that should influence your choices. Function is the most important of these. What do you need the window or door to do, and will your choice achieve it? For every opening, ask yourself why you need it. Is it to provide light, an access point, fresh air or to look nice? Then consider cost. Often a homeowner’s aspiration does not match their budget. But before settling for less, explore the alternatives that may give you close to what you want and fall into budget. For instance, wall-to-wall Crittall feature can be recreated for a fraction of the cost when made by a non-branded manufacturer. The next factor is style. Style can be driven by choice of material, size, quantity and composition of openings. What ‘look’ do you want to achieve with your extension? You may decide on a traditional feel in keeping with the rest the of the property or decide on a distinct break from tradition and opt for something more modernist. A newer home may benefit from a contemporary feel. In fact there are dozens of architectural styles and your fenestration choices should be sympathetic to the overall design. Lastly consider how the fenestration selections will sit within and against the immediate street scene and other nearby houses.

There are 5 fenestration groupings that you could encounter for your extension: windows, doors, balustrades, bespoke features and internal glazing.

Windows. As far as residential extensions go, there are three types of window. Conventional, sloping roof and flat roof window. A conventional window refers to a window in the wall. There is an infinite number of conventional window sub-categories, but the main ones are casement type (think of classic UPVC), sash type and tilt-and-turn type. Roof windows sit within the slope of the roof and can either open outward completely if top-hung, or half in, half out when on a centre pivot. You will get to know these very well if you extend up into the attic. Thirdly, we have flat roof windows, which, as the name suggests, sit within flat roofs. Roof windows come in all shapes and sizes, but typically you will be selecting flat glass, curved glass, plastic domed or lantern-type. For all the above you will be deciding whether they are fixed or openable (if so, which parts), manually operated or automatic, single, double or triple glazed, coated or clear, and more.

Doors. Okay so external doors are a world unto their own where the choice of material size, shape, operation type, colour, finish, locks, security, thresholds and letter boxes are but some the details you need to pin down when selecting doors. All this whilst keeping in mind the over-arching design considerations previously mentioned.

The next three are not by definition fenestration. They are here because they will be supplied by the same industry which produce the windows and doors.

Glass balustrades. You will come across the need for balustrades in one of two scenarios; either part of a balcony (Juliet or traditional) or for a roof terrace. Depending on the size of the space, these pieces of glass can get very big and very heavy. So heavy in fact that they may even need structural support of their very own, and you will benefit by keeping design and cost in the same breath when making decisions. Glazing maybe transparent or opaque and the finish should be congruent to the accompanying accoutrements – the ironmongery handrails and fixings.

Bespoke features. A bespoke glazed feature is pretty much anything you need to serve a particular area, that you cannot pick out and order from a supplier’s stocked inventory. You may need a non-standard window to span wall-to-wall, floor-to-ceiling to create a panoramic vista from a new bedroom, a small triangular window inset to a dormer cheek, a replication of a historic gothic opening or perhaps a stained-glass feature. Whatever the intention, done well, bespoke glazing can be a real focal point in any new space.

Internal glazing. In place of a traditional internal partition, you may opt for glass. Glass partitions are fantastic for providing the separation of a conventional room, whilst simultaneously giving the wider area in which it sits, a sense of unified wholeness and light. Very Zen. The fire safety requirement can be onerous and manufacturing lead-times long, so understand the implications of both in advance of locking your decisions in.

The upshot of pinning down your fenestration specifications on plan, is that there are a very many ways to plug the openings in the extension walls and roof with doors and windows, and it is imperative that you consider your choices from all angles before finalising your decisions.

If you would like some free planning advice, get in touch with us.