Conversion Headroom and Volume Questions Checklist

Measure the height at the highest point and at several points across the floor, and write down where each measurement was taken.

A single central measurement flatters almost every loft and cellar, and anybody assessing the space will ask where the number came from.

Note where the height stops being generous and begins falling away, and mark that line on the floor with tape so you can actually see it.

Seeing the line on the floor tells you more about the future room than any figure written on a page.

Record whether the existing floor is level, and note every point where it dips, slopes or steps across the space.

Height measured from an uneven floor is not one measurement, and cellar and garage floors are often deliberately laid to fall.

Whether an uneven floor can be levelled, and what that would involve, must be established by a suitably qualified professional.

Write down the height under any beam, purlin, collar or duct crossing the space, because that is the height people will meet with their heads.

The tightest crossing point usually governs how a space feels and is regularly left out of an owner's notes.

Photograph the space with a tape or a rod held vertically in shot, so the proportions can be read by somebody who was never there.

Photographs without anything in them to give a scale are almost useless once you are describing the space to somebody else.

Write beside each measurement what it was taken to, since a measurement to the top of a joist and one to a boarded floor are different numbers.

Owners and professionals frequently measure to different surfaces, and the gap between them is enough to change a whole conversation.

Walk the space upright and mark where you have to start ducking, then pace out the area inside that line and note it roughly.

The standing area is what decides whether a conversion is worth doing, and it is usually smaller than the floor area shown on a plan.

Note what the strip outside the standing line could still do, whether storage, a low run of cupboards, a desk or honestly nothing at all.

Low perimeter space is genuinely useful when it is planned for and simply wasted when the layout ignores it.

Consider the shape of the standing area, since a narrow ribbon down the middle behaves very differently from a square patch of the same size.

Two spaces with the same usable area can be completely different rooms depending on how that area is shaped.

Note who in the household is tallest and walk the space with them, rather than judging the height on your own.

Households routinely measure with whoever is holding the tape and only discover the problem once somebody else uses the room.

Note where somebody would stand still for any length of time, such as at a worktop, a basin or a wardrobe, and check the height at each of those points.

Standing height matters most exactly where people stop moving, and those positions are easy to identify now.

Consider whether the space would be used seated for most of the time, and write down where the seated positions would fall.

A room used mainly sitting down can work with height that would be unacceptable in a room people walk across constantly.

List every timber crossing the space at or below head height, including collars, ties, braces and anything that looks as though it was added later.

These members are the commonest reason a loft that measures well turns out to be unusable in its present form.

Whether any timber crossing the space can be altered or removed is entirely a matter for a suitably qualified structural professional.

Note any water tank, cylinder, vessel or run of pipework standing in the space, and where each sits relative to the usable area.

Tanks are usually placed where the height is greatest, which is exactly where you would want to stand.

Note the track, springs and motor of any garage door, and how far into the space they reach when the door is fully open.

Garage door gear commonly occupies the full width of the ceiling zone and is forgotten until the layout has been drawn.

Record any duct, flue, soil pipe or cable tray crossing the space, and photograph where each one enters and where it leaves.

These items have to go somewhere if the space changes use, and where they could go is a question worth asking early.

Moving a flue, duct or soil pipe involves considerations that must be settled by a suitably qualified professional.

In a cellar, note the shape of the ceiling, including vaults, haunches and any brick arch that drops lower than the rest of it.

Cellar ceilings are rarely flat, and the lowest part of an arch often falls exactly where a doorway would be wanted.

Note anything fixed to the underside overhead, such as light fittings, an aerial cable, a hatch or a folding ladder, and where each one lands.

Small fixed items are easy to overlook on a sketch and awkward once the layout has been drawn around them.

Ask what would be added to the floor of the space and what that build-up would take from the height, before assuming today's figure survives.

Owners plan against the height they measured, and the finished height is very often a different number.

What has to be added above or below the existing surfaces can only be determined by qualified professionals for your property.

Ask the same question about the ceiling or the underside of the roof, since linings and anything running above them also take a slice.

Height disappears from both directions in a conversion, and both directions should be asked about at the same time.

Write down the height you are assuming the finished room would have, and mark it clearly as an assumption until somebody qualified confirms it.

An assumption that is labelled can be corrected later; an assumption that has quietly turned into a fact cannot.

Ask where the height would be tightest once everything has been added, and whether that point falls somewhere people actually need to stand.

The tightest finished point is what people experience, and it is rarely where the tightest measurement is today.

Note whether any part of the space would end up with a step in the floor or the ceiling line, and where that step would fall.

Steps appear wherever build-ups differ between areas, and it is far easier to place one deliberately than to discover it.

Ask whether reducing any build-up is even a discussion here, and treat whatever you are told as belonging to the professional who said it.

Owners often assume a layer can be thinned to buy back height, and whether that is possible depends entirely on the property.

Reducing any part of a floor, ceiling or roof build-up in order to gain height is a decision for qualified professionals only.

Ask whether lowering the floor of a cellar or garage is something that could even be discussed at this property, and record the answer you get.

Lowering a floor changes what surrounds it in ways only a professional can assess, and the answer varies enormously between properties.

Whether a floor can be lowered, and what it would involve below and around it, must be established by a suitably qualified structural professional.

Ask whether raising or altering any part of the structure above is a realistic conversation, and note what you are told before designing around it.

Owners frequently assume a roof or ceiling can be lifted, and that is the single most consequential assumption made in a conversion.

Altering roof or floor structure to gain height is a matter for qualified professionals and must also be confirmed locally.

Consider whether opening the room up into the volume above, rather than keeping a flat ceiling, is something you would actually want.

An open or partly open ceiling changes how a converted space feels, and the choice pulls several other decisions along with it.

Ask whether taking down an existing added or suspended ceiling would reveal usable height, and what might be found behind it.

Added ceilings are common in garages and cellars, and they sometimes hide useful height and sometimes hide something else entirely.

Note that gaining height in one part of the space usually takes something from somewhere else, and ask what the trade would be in each case.

Routes to more height generally take something from somewhere else, and hearing what that is before choosing keeps the decision honest.

Ask what each option would mean for the rooms immediately beside and below the space being converted.

Height changes rarely stop at the edge of the room, and the neighbouring spaces are usually how the household notices.

Stand in the position where you would spend most of your time and describe honestly whether the space feels enclosed or generous.

How a space feels is real information, and it is something an owner can report better than anybody else.

Note where daylight currently enters, and whether it arrives high in the volume or low down near the floor.

Light entering high in a space tends to make the low areas feel more tolerable, and where it enters is settled early.

Consider whether a sloping ceiling would be experienced as a pleasant shape or simply as a room with a corner missing from it.

Slopes can be the most appealing part of a converted space or the thing people complain about, depending on where they fall.

Note how far you can see across the space in its longest direction, and what would interrupt that view once the space is divided up.

Long sight lines make a space feel larger than its measurements, and partitions remove them very quietly.

Consider the volume you would be warming compared with the rooms you already live in, and put that comparison to a professional as a question.

A tall or open volume behaves differently from a conventional room, and the comfort question is worth raising early.

How a converted volume would be warmed and how it would perform in use can only be assessed by suitably qualified professionals.

Note where the space would feel tightest to somebody arriving for the first time, rather than to somebody already used to it.

Households adapt to a space quickly, and a first impression is much closer to how the room will be judged later on.

Draw a rough section through the space showing the highest point, the low edges and where the floor sits, however crude the drawing turns out.

A rough section communicates a conversion space far more clearly than a plan, and hardly any owner produces one.

Write the date beside each measurement along with the surface it was taken to, since surfaces change as a project moves along.

Undated measurements taken to unknown surfaces get quietly mistrusted and then taken all over again by somebody else.

Note every measurement you could not reach or were not confident taking, and say so plainly rather than estimating the figure.

An honest gap is useful information, while a guess presented as a measurement is what causes trouble further down the line.

Do not enter an unfloored loft or an unlit cellar to take measurements yourself; ask a qualified professional to take them instead.

Keep the photographs, the sketch and the written notes together with the measurements so that nobody has to reunite them later.

Height evidence is used repeatedly through a conversion and is only useful while it all stays in one place.

Ask which measurements a designer or engineer would take themselves, so you know which of yours are only a starting point for discussion.

Owner measurements exist to frame the conversation, and knowing that keeps everybody's expectations in the right place.

Confirm locally what applies to head height in the kind of space you are converting, and note the date and who answered you.

Two spaces in the same house can be treated quite differently depending on what each is to be used for, so the question needs asking about this one.

Head height expectations for habitable space are set locally; only the responsible body can tell you what applies to a conversion at this property.