Measuring checklist before ordering a greenhouse, pergola or outdoor sauna

Reliable site measurements cover more than length and width. This checklist covers the plot, foundation, heights, wall connections, doors, service routes, drainage and installation access.

Accurate measuring is the basis for a reliable order. For a greenhouse, pergola or outdoor sauna, two roughly measured side lengths are not enough. Heights, diagonals, slopes, foundations, roof overhangs, circulation space, service routes and access to the installation site also matter.

This guide helps private builders, planners and installation teams record a site systematically. It replaces neither product-specific drawings nor checks of local requirements. The documents for the chosen model and the rules applying at the installation site always remain decisive.

Measure the site before selecting the final model

Do not begin by asking which nominal product size will just fit in the garden. First establish the genuinely usable area. This reveals which form, orientation and size are technically sensible.

Mark plot boundaries, buildings, walls, paths, trees, beds, inspection chambers and service lines. Planning or permit requirements may also need checking. The article Planning permission for a greenhouse or pergola provides initial guidance, but only the competent authority can give a binding answer for the individual project.

Consider more than the structure itself. Doors, roof edges, drainage, maintenance and assembly all need space. A model may fit geometrically yet remain impractical if a door cannot open fully or a side wall cannot later be reached.

Four measuring rules that always apply

1. Measure twice: Record important dimensions at least twice. Where possible, two people should check longer distances.
2. Do not assume square corners: Terraces, walls and existing foundations are often not perfectly square. Measure both diagonals.
3. Record heights separately: A flat drawing does not show a slope. Record height differences at every corner and notable intermediate point.
4. Separate existing and planned dimensions: Write measured values, intended positions and product dimensions in separate columns. This prevents assumptions being treated as existing measurements.

Do not round prematurely to a convenient size. A rounded figure may be enough for selection, but actual product and connection dimensions must be checked before ordering or building the foundation.

Prepare tools and information

• a sturdy tape measure and suitable distance meter;
• a spirit level, straightedge or suitable levelling device;
• string, pegs, chalk or removable marking tape;
• a square, plumb line and, if needed, a ladder for safely reachable height measurements;
• notepad, site-plan sketch and camera for documentation;
• product drawing, foundation plan and assembly instructions for the intended model;
• information on underground services, drainage and existing foundations.

Further product areas and planning advice are available under Useful information, in Greenhouses and conservatories and in the Sauna section. For project-specific questions, use Contact before foundation work to clarify which documents govern the selected product.

Create a complete site plan

Draw the installation area in plan view. The sketch need not be to scale, but it should have an unambiguous reading direction. Mark north, all boundaries and at least one fixed reference point, such as a building corner.

Record distances from the planned structure to at least two permanent reference lines. Add side lengths, diagonals, door swing areas and maintenance routes. A building connection also requires a wall elevation.

Plan content	Record
Plot and existing features	Boundaries, buildings, walls, paths, planting, chambers
Planned structure	Outer outline, orientation, doors, roof edges
Heights	Corner heights, slopes, steps, thresholds and wall connections
Services	Service routes, outlets, drainage direction
Logistics	Access, transport route, pinch points and assembly area

Measurements needed for every structure

The following values should be available regardless of product type:

• available overall length and width;
• both diagonals of the marked area;
• heights at every corner;
• distances to boundaries, walls and obstructions;
• minimum clear width of the transport route;
• available height beneath branches, roof edges or cables;
• width and opening direction of adjacent doors and gates;
• positions of chambers, pipes and cables;
• space for assembly, ladder placement and later maintenance.

Measure extra intermediate points on irregular areas. An apparently straight wall may bulge, a terrace may be trapezoidal and a kerb stone may project into the intended post position.

Choose the product type before fixing the footprint

The structure changes the requirements for site and foundation. A wall-mounted pergola needs a suitable connection wall; a freestanding structure needs defined support points all round. The comparison Wall-mounted or freestanding pergola helps with this basic decision.

The roof function also affects drainage, clear height and adjoining façades. Read Bioclimatic or classic pergola and the background article What is a bioclimatic pergola?.

For saunas, rectangular cabins and barrel forms differ in spatial effect, access and usable surrounding space. Compare, for example, Elma S, Elma L and the HC150 barrel sauna using their own product documents, rather than garden photographs alone.

Measuring checklist for a greenhouse

• Document sun path, shading and orientation of the long axis.
• Check the footprint, including the foundation or plinth area.
• Allow for the door side, opening route and threshold-free access.
• Check eaves and ridge areas for branches, cables and roof overhangs.
• Keep room for window openers, ventilation components and cleaning.
• Plan water access, rainwater routing and routes for planting soil.
• For wall models, record sills, downpipes, plinths and façade projections.

Historically inspired or geometrically divided structures may have additional axes and connection details. The article on Victorian greenhouses shows design relationships, but only the drawings for the selected model are binding for measurement.

Measuring checklist for a pergola

• Measure terrace width and depth at several points.
• Check every intended post position on load-bearing ground.
• Allow for roof overhangs and any integrated drainage routes.
• Check clear height against doors, windows and shutters.
• Plan opening and movement space for louvres, shading or glazing.
• Record existing terrace runoff and possible splash-water zones.
• Document exposed sides and surroundings for site-specific planning.

For sizing, the Pergola size guide is useful. Material choice and intended use are explained in Aluminium or wood . If side walls are planned, measure sliding routes, stops and ground levels too; see Pergola with glass walls.

Measuring checklist for an outdoor sauna

• Record the entire installation area, including entry and maintenance access.
• Mark door position, opening direction and a safe approach area.
• Check foundation points or continuous bearing surfaces against product documentation.
• Document service routes for the planned technical equipment.
• Clarify drainage and cleaning options for the site.
• Check distances to vegetation, buildings and other facilities.
• Assess the transport route for width, height, bends and bearing capacity.

Different models must not be planned from a shared standard footprint. Check documents for HC 180, HC 225, HCF 225, HCF 300 and LC 225 individually. The article Choosing a wooden or barrel sauna offers general orientation.

Measure the foundation and terrace

An existing surface is not automatically a suitable foundation. Record build-up, edge distances, joints, slope, visible damage and accessible information about the substructure. Whether bearing capacity, frost resistance, anchoring and drainage are adequate must be assessed professionally for the specific structure.

For pergolas, the Pergola foundation guide summarises key planning questions. Transfer drilling or bearing points only from the approved product drawing. Do not estimate distances from a product photo.

How to check the marked-out rectangle

1. Mark outer edges with string.
2. Measure both long sides and both short sides individually.
3. Record the two diagonals.
4. If diagonals differ, correct the corners and measure again.
5. Level heights at every corner.
6. Then secure positions against a fixed reference point.

Equal diagonals are an important check, but do not replace checking every side. For complex layouts, check each rectangular section separately.

Additional checks for wall-mounted structures

Create a dimensioned wall elevation. Record façade width, usable connection height, windows, doors, shutter boxes, lights, downpipes, vents, outdoor taps, projections and plinth offsets. Check the wall at connection-profile height as well as near ground level.

The suitability of the wall and its fixing must be assessed for the individual property. Insulation, cladding or unclear wall construction must not be replaced by assumptions. Involve a qualified professional early where needed.

Plan doors, routes and interior space

Mark every door in its open position. Check whether it conflicts with garden paths, furniture, raised beds or existing building doors. A comfortable main route should not be narrowed by a post, bench or technical fittings.

Plan the interior before finalising orientation. In a greenhouse, planting tables and wheelbarrow routes matter. Under a pergola, tables, chairs, a grill or outdoor kitchen define circulation space. A sauna requires safe access, changing space and a route to the building. Find terrace ideas under Pergola ideas for terraces and gardens.

Services, drainage and site conditions

Add existing and planned service lines to the site plan. These include electricity, water, drainage and other installations. Connections should only be planned after checking the chosen product requirements and applicable local technical rules. Fixed outdoor electrical work should be carried out and certified where necessary by a REWS-authorised professional with the appropriate scope.

Observe the site in rain where possible. Record flow directions, puddles and water running from the building. Also check shading, leaf fall, wind exposure and seasonal conditions. Guidance on seasonal use is available in Pergola in winter. Site-specific loading assumptions and local requirements must be checked separately.

Measure the delivery and installation route

The route from unloading point to installation area is part of the survey. Record the narrowest clear width and height, tight bends, steps, slopes, soft ground, gates and low branches. Check whether long components can pass around corners and whether enough room is available at the destination for sorting and assembly.

Also document restrictions on shared areas or narrow approaches. A sufficiently wide garden gate does not automatically mean every component can travel the entire route.

Practical measuring sequence: Anna Koku Skola

The Anna Koku Skola image sequence should be understood as one connected installation sequence. It suggests a clear workflow for measuring: first record the whole site, then mark out the building outline, then check foundation and connection areas, and finally keep the assembly environment clear.

1. Record existing conditions: Note fixed reference points and obstacles on a sketch.
2. Transfer the outline: Make the intended footprint visible with string.
3. Check geometry: Measure sides, diagonals and heights independently.
4. Check connections: Compare wall, ground and drainage areas with documentation.
5. Simulate use: Open doors, walk routes and mark interior areas.
6. Confirm logistics: Make a final check of the transport route and assembly area.

The individual images must not be interpreted as separate projects. They document the same installation context from different stages or viewpoints.

Worksheet for measuring before ordering

Check point	Existing value or result	Status
Available length and width	Enter	Open/checked
Diagonal A and B	Enter	Open/checked
Heights at every corner	Enter	Open/checked
Distances to boundaries and existing features	Enter	Open/checked
Door and walking routes	Describe	Open/checked
Foundation condition	Describe	Open/checked
Services and drainage	Mark	Open/checked
Transport route	Enter narrowest point	Open/checked
Product drawing checked	Note document version	Open/checked

Final check before approving the order

• The exact model and its configuration are clearly defined.
• All measurements come from the actual site.
• Footprint, overhangs and opening areas were distinguished.
• Diagonals and heights have been checked.
• Foundation and anchoring were not judged from the visible surface alone.
• Wall connections and façade obstructions are fully documented.
• Accessories and planned extensions are included in space requirements.
• Transport and assembly route are plausible.
• Local requirements have been clarified with the relevant authorities.
• Outstanding technical questions are resolved before approval.

Information about the company is available under About us . Other garden areas that may matter in overall planning can be found under Garden sheds.

Check drawings and instructions again after ordering

Once order-specific documents arrive, a second comparison is required. Check model name, orientation, external dimensions, foundation points, door positions and connections. Do not start foundations or service work from an old sketch, a similar model or an on-screen image without checking dimensions.

Give the foundation contractor and installation team the same current document version. Changes at the site must be incorporated into the documentation and checked again.

Measure for future maintenance, not only assembly

A structure may be installable yet difficult to maintain. Keep areas accessible for cleaning, fitting care, checking drainage routes and replacing reachable components. Do not plant vigorous shrubs directly beside components requiring regular inspection.

Also consider ladder placement, window cleaning and access to roof edges. Required clear space depends on the model, surroundings and maintenance task, so no general fixed clearance should be adopted as a binding dimension.

Frequently asked questions

Should I order using the floor area shown on a product page?

No, not without checking. Establish what the measurement refers to and whether roof overhangs, fixing zones or circulation areas also need allowance. The documents for the exact selected model are decisive.

How can I tell whether a marked-out rectangle is square?

Measure both diagonals. In a geometrically correct rectangle they are equal in length. Opposite sides must also match, and corner points should be checked on the intended height plane.

Can an existing concrete terrace be used?

Possibly, but not simply because of its surface. Build-up, condition, slope, edge distances, bearing capacity, frost performance, anchoring options and drainage must suit the project. A professional assessment may be needed.

How much space should remain around the structure?

There is no universal dimension. Clearance depends on doors, roof overhangs, cleaning, assembly, drainage, the plot situation and local requirements. It must be defined for the specific model.

What must be measured for a lean-to greenhouse or wall pergola?

In addition to the footprint, you need a dimensioned wall elevation. It must include connection height, wall width, plinth, openings, services, downpipes, projections and wall construction.

Do I need to measure myself if Bloomcabin provides product drawings?

Yes. The drawing describes the product, not the actual conditions on your plot. Only comparing product information with the site survey shows whether installation, use and assembly are possible.

When should the installer be involved?

Ideally before foundation construction and service installation, especially with slopes, tight transport routes, wall mounting or unclear existing conditions. This clarifies assumptions before difficult-to-correct work begins.

What should I do with a sloping garden?

Measure heights at every corner and relevant intermediate point. Do not plan only from the average slope. Suitable foundations and ground adjustments must be set for the site and product.

Must planned accessories be included in the survey?

Yes. Side walls, shading, gutters, technical components, steps, furniture and future extensions can affect space, connections or foundation areas.

What is the most common measuring error?

Often only a nominal length and width are measured. Diagonals, height differences, door movements, overhangs and installation routes are overlooked. A complete site plan prevents this narrow approach.