What We Do on a Window Survey

For all our projects, we ask for 10% deposit when a customer asks us to come and survey the windows (or openings for windows) to their property.

We treat our surveys as accurate production notes, not a 10 minute walk-around with a salesperson! A proper survey has at least two of our employees – one who has extensive knowledge of the product and the actual installer who will be fitting the windows. Obviously, those skills often overlap, but most employee’s jobs are mainly based in either the theory or the practice of installing. Every opening is considered in terms of overall frame size, any issues regarding frame depth, access, building material on the outside, plaster/tiles on the inside and really anything that would somehow interfere with a smooth fitting.

So, it’s very important that both you and your home are ready for us to go through the survey procedure.

For replacement windows, it is relatively straight-forward. We ask that everything looks as correct as it can be on paper: largely that you’re happy with the price and product chosen in each position. Different products have slightly differing installation methods and frame depths, so it’s important that we survey for the correct one. Also, we ask that we are able to walk up to every window from at least the inside of the home. Preferably both inside and out, but we understand that some windows are simply not possible to reach from the outside without a complex scaffolding arrangement (such as a window directly above a conservatory).

In a new-build property, the above is still important, and there are some more areas that we would like you to consider. Each structural opening must be fully formed, including the lintel, and in the same state that we would find when we come back and install. Again, we understand that this is not possible in some cases (when render is involved for example). Where this is not possible, we must have a detailed drawing showing the build-up of what will be changing. We also ask that you alert us to any potential risks on-site, such as any work being done directly above us, before we start measuring.

The Basics

Now we’ve done the overview, lets get onto some of the things we’re going to be talking about during a survey.

Sizes, we need to know the width and height of the opening we will be putting the window into. On old stone buildings especially, this can be challenging to do without many years of experience. Multiple measurements get taken from each opening, along with using a straight edge or level to check for protrusions and squareness of the openings. Our windows must be fitted square and level with a gap for weather sealing. Uneven stonework around a window can sometimes need cutting back to avoid extreme differences in tolerance in different places around the frame.

Window Cills: do we need to leave space for them when we install? If you would like to have timber cills, they will need to be made before we install. Pressed aluminium cills are made after the windows have been fitted. If you already have tile or stone cills, you may not need any cills from us at all.

Door cills: must be taken into account by the installers too. Doors don’t necessarily have to have a cill; you’ll still have a threshold at the base. But the inability to direct rainwater away – often needed for disabled access-friendly level thresholds – means it’s important to consider how water can naturally run away from the building.

It’s incredibly important to let us know if any floor levels are going to change for any reason. The top of a door’s threshold must be high enough so that the door can physically open. Changing a floor covering to a different thickness can result in a door that you can’t walk through…

Plastering and Pointing

If your current windows are more shallow than the windows we will be fitting, we may need to cut back plaster inside the window aperture; the window must be set-back from the exterior of the house to avoid water pooling on top of the upper frame.

Many houses have their windows pointed in – this is a common way to weather-proof the exterior of a window, and we need to size our windows correctly to leave enough room for this detail.

Removable casements on opening windows: when installing we may in rare cases our installers may need to be able to remove the window frame to install the window; this is most common for heavy, large windows at a height where we can’t use mechanical lifting.

Retaining Construction Details

Does the flashing or cladding need to be reinstated or remade? On most timber-clad homes, the timber overlays the window, this may need to be removed or cut-back to allow us to remove the previous window. This is often the case for rendered properties as well.

Do you have a splayed reveal (where the internal space near the window angles outwards into the room)? Similar to us needing to cut back plaster to allow for a modern, deeper window – this additional depth means we need to consider how to neaten up that detail after the new window is installed.

Taking Care of Your Home and Our Installers

We always use dust sheets, carpet protectors and clean up after ourselves as best we can. Unfortunately though, building dust still has a habit of sneaking into annoying places. We’ll point out any items which you may want to move away from where we’re working: common items are flowers, musical instruments, and computers.

Our fitters will need good access to install, from both inside and outside. Again, common areas we’ll ask for are having beds and chests of drawers moved away from the window inside. Exterior scaffolding can sometimes come across as unnecessary, especially if you’ve seen plastic windows being installed in a similar position off nothing but a ladder. It’s worth bearing in mind that our units are significantly heavier and our installation details are far more intricate – there’s no point buying a Class 4 airtight window from us and not matching the airtight level in the installation.

Moving larger windows and doors often needs additional consideration. We’ll be looking for access requirements, and lifting requirements. Most commonly, a 3m wide sliding door will be fully constructed and glazed in its Danish factory; the full size and weight arrives with us at your home. So a customer choosing that type of sliding door means we have to plan how to move hundreds of kilograms safely off the delivery vehicle and into position.

Joining multiple frames

this can happen for a number of reasons, but the most common is a Door with a sidelight or window attached, and a bay window.

if the door with a window situation, we need to know where the join will occur, usually the window will be butted against the door after the door has been fixed in place, but this means working out the exact position of them can be more complex, further if the window is to line through with the door, any mullions or glazing bars must be taken into account

Doors with sidelights are much more simple; usually we treat a door with separate sidelights as if it is a single unit, attach them together on-site then install as usual

The Two Most Complex Areas

Built-in sliding sashes, often requiring a builder alongside us on the survey. Ensuring the old box sections are extracted, and filling in that space correctly is honestly beyond what most window installers are comfortable with. Many companies will avoid this stage by simply leaving the old boxes in place and placing new windows up against that old timber section but, for perhaps obvious reasons, we’re not comfortable relying on an unknown section of wood to be a solid sealing and fixing point.

Bay windows can be extremely complicated! Structural versus non-structural will send us down very different paths of thinking. And it’s important for us to provide or recommend the best post solution based on the window product and the building itself. Unlike the plastic bay windows we’re often replacing, timber doesn’t have a naturally hollow section where supporting steel pole can be inserted through… This is another area where a builder may need to be involved to help with structural elements; windows should never be used as structurally-supporting items!

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