Conservatory and Garden Room Comparison Preparation Checklist

Write down the activities the new room has to support, in order of importance, using plain words such as eating, working or sitting.

An ordered list becomes the yardstick for every option and stops the comparison drifting towards whichever one is described most attractively.

State honestly how often the room would be used, and whether that holds in every season or only once the weather is mild.

All season occupation and fair weather occupation lead to genuinely different answers, and stating which one you want is the decision the rest hangs on.

Note which existing room the new space would open from, and whether that room would become a corridor once the new one exists.

New rooms at the back frequently turn the room behind them into a passageway, which is rarely mentioned until it happens.

Record which existing windows would end up looking into the new space rather than at the garden, and which rooms they serve.

Building over an existing window changes the light in a room that currently works, and the loss is easy to overlook.

Note the furniture that must fit, such as a table with chairs pulled out, and whether the intended footprint really accommodates it.

Dining use in particular is often assumed and then found to be impossible once the doors and radiators are placed.

Write down what would make the finished room a disappointment, such as being too warm to sit in or too cold to use in winter.

Naming the failure conditions gives you the questions to ask about every option and keeps the comparison grounded.

Note which options under discussion have a fully glazed roof, a solid roof, or a solid roof with roof glazing in part of it.

These are quite different things that are often given similar names, and separating them is the first step in an honest comparison.

Consider what a solid roof would take away, such as the sense of sky and the light reaching the back of the existing room.

Solid roofs solve comfort problems and remove something people genuinely care about, and that trade should be stated openly rather than glossed over.

Ask a qualified professional how each option would affect daylight in the existing room behind it, and record what you are told.

The room behind is the one that changes most, and its daylight is rarely part of the usual description of any option.

Note which way the new room would face and how much direct sun that elevation receives through the morning and afternoon.

Orientation changes which option is sensible, so any comparison that ignores it is comparing the wrong things.

Record whether trees, fences or neighbouring buildings shade the area, and whether that shading holds in every season or thins once leaves drop.

Existing shade alters the comfort picture significantly and is easily observed before any option is chosen.

Ask a qualified professional what each option involves in terms of requirements, and confirm locally what applies to your property.

Different arrangements are treated differently, and that difference frequently matters more than the appearance.

How each option is treated under local requirements can only be confirmed with your local authority and a qualified professional.

Ask a qualified professional how each option is expected to behave in the warmest weather, and what shading or ventilation would be discussed.

Warm weather performance is the most common complaint, and it is a design question rather than something to fix afterwards with blinds.

Thermal comfort and ventilation are technical matters that depend on construction and orientation, and must be advised by qualified professionals.

Ask how each option would perform in the coldest weather and what heating arrangement is envisaged for the room.

A room that empties out as soon as it turns cold is a different proposition from one that stays in use, and this question is where the options separate.

Note whether heating for the new room is assumed to come from the existing system, and ask whether that is realistic.

Extending an existing heating system to a new room is a question for a qualified installer rather than an assumption in a sketch.

Do not let a sketch assume the existing system stretches to a new room. That is an installer's judgement, made after looking at what is already there.

Consider whether shading or blinds are part of your expectation, and record that they are wanted rather than assuming they are included.

Shading for a glazed roof is a substantial part of the arrangement and is better discussed at the start than as an afterthought.

Note how you expect the room to be ventilated, including whether openings can be left open safely in rain or when you are out.

Ventilation strategy affects the layout and the doors, and owners usually assume more openings than end up in the design.

Record whether noise from rain on a glazed roof would trouble you, based on any similar room you have spent time in.

Rain noise is a common and entirely avoidable disappointment, and it varies significantly between arrangements.

Photograph the whole rear wall including the ground, the windows, the gutters and anything fixed to it, before any option is chosen.

Everything on that wall becomes part of the project, and a full photographic record prevents surprises when the design appears.

List what is fixed to the rear wall, such as a boiler flue, vents, an external tap, lighting, cables or a waste pipe.

Each of these items needs a decision, and several of them involve people other than the builder.

Anything involving a flue, a vent or an appliance on the rear wall must be assessed by qualified installers before it is enclosed or moved.

Ask a qualified structural professional what any opening in the existing rear wall would involve and what would need to be established first.

Whether and how the existing wall can be opened is the biggest single variable between the options and belongs with a professional.

Whether an existing wall can be opened, and what that requires, can only be established by a qualified structural professional.

Note where drains, gullies and access covers sit along the rear wall and in the area the new room would occupy.

Building over drainage raises questions that are far easier to deal with before a footprint is agreed.

Building over or near drainage involves requirements to confirm with qualified professionals and the relevant drainage undertaker.

Note whether the garden falls towards the back of the house or away from it, and where water currently ends up after a downpour.

A garden that drains towards the house is a constraint on every option, and it is much easier to observe now than to argue about once a floor has been laid.

Consider what a new roof would sit beneath at first floor level, and whether it affects a window, a vent or access for maintenance.

The relationship with the floor above is often ignored until the roof line appears on a drawing.

Note whether doors would remain between the existing room and the new one, and record who wants them and why.

Retaining doors changes both the feel of the space and how each part performs, and it is a decision worth making deliberately.

Consider what would happen to the existing room if the new space were cold and the doors were left open in winter.

This is the practical reason many owners find themselves keeping the doors shut and using the new room far less than expected.

Record which way any doors would swing and what furniture would have to sit clear of them in both rooms.

Door swings quietly consume the usable area of both rooms and are easy to test on a rough plan.

Note how the new room would open to the garden, whether the doors slide or swing, and where an open leaf would sit.

Doors that swing outwards need clear space on the terrace, and sliding arrangements park their leaves against something.

Consider whether the threshold to the garden should be level, and ask a qualified professional what that involves here.

Level thresholds to a garden are popular and have implications for water and drainage that need professional input.

Where a floor meets an outdoor terrace, the detailing carries water and drainage consequences. Ask a qualified professional what it involves before it is drawn flat.

Note how secure you need the new doors to be, particularly if the garden is reached from a rear path or shared access.

Security of a large glazed opening at the back of a house is a legitimate part of the comparison between options.

Ask how any roof glazing would be cleaned, from inside and outside, and who would realistically do it.

Roof glazing collects dirt, leaves and moss, and access for cleaning is rarely mentioned when the option is first described.

Note whether trees overhang the area and whether leaves, sap or blossom would land on a glazed roof each autumn and each spring.

Overhanging planting turns a glazed roof into a maintenance task and can be observed before deciding anything.

Record any experience you have of condensation in a similar room, including where it appeared and in what weather.

Condensation behaviour is a real part of the comparison and your own observations are worth bringing to the conversation.

Why condensation occurs in any particular room is a technical question for a qualified professional rather than something to infer.

Ask where gutters and valleys would run on each option, and how they would be reached to be cleared.

Blocked gutters on a rear addition cause damage at the junction with the house, and access for clearing them matters.

Note which parts of each option would need periodic attention, such as timber, seals, coatings or moving parts.

Understanding the upkeep obligation is part of choosing, and it is easier to discuss before a construction approach is settled.

Write down who in the household would carry out or arrange the upkeep, and whether that is realistic in the long term.

An honest answer here sometimes changes which option a household should choose.

Note how much solid wall each option leaves, and what furniture you would want to place against a wall.

A room with almost no wall cannot take a sideboard, a bookcase or a television, which surprises people after they move in.

Record where heating would be placed and what that rules out along that stretch of wall or floor.

Heating positions and furniture positions compete for the same limited space in a heavily glazed room.

Consider whether the floor should continue from the existing room without a change of level or material, and note your preference.

Floor continuity does more than anything else to make a new room feel like part of the house rather than an addition.

Note whether furnishings, artwork or a piano would suffer in strong sunlight, and raise that when the glazing is discussed.

Sensitive contents are a genuine constraint on how much glass is sensible and are rarely mentioned in the brief.

Write down where you would want sockets, lighting and switches, given how little wall there may be to put them on.

Electrical positions in heavily glazed rooms need planning early because the usual walls simply are not there.

All electrical arrangements are work for qualified installers, and their positions should be agreed with them rather than assumed.

Consider how overlooked the new room would be from neighbouring windows and gardens, and whether that affects how you would use it.

A largely glazed room close to a boundary can feel exposed in a way the existing house does not.

Write each option against the same list of requirements you set out at the start, and note where each one falls short.

Comparing against your own requirements rather than against each option's description is the whole point of the exercise.

Record what each professional or supplier told you, in their words, and note anything that contradicts something else you heard.

Contradictions between accounts are the most useful thing in the whole comparison because they show where to ask harder questions.

Make the local enquiry separately for each option, rather than assuming an answer given about one form of rear addition carries over to another.

A comparison unravels most often when an answer obtained about one arrangement is quietly applied to a different one late in the process.

Note what each description does not mention, such as the floor, the heating, the doors into the house or reinstating the garden.

Comparisons are usually distorted by what has been left out rather than by what has been described.

Write down what you would do if none of the options meets the requirements you set, including doing nothing for now.

Having a fallback keeps you in a position to decide calmly rather than accepting whichever option is in front of you.