Read the window schedule before requesting a quote
Understanding window planning
At first glance, a window schedule can look like a table of abbreviations, dimensions and item numbers. In reality, it determines whether three suppliers are pricing the same scope or merely similar-sounding windows. Reading it before requesting a quote reveals missing information early: is the dimension the structural opening, outer frame size or clear opening? Is the opening direction viewed from inside or outside? Does the U-value refer to the glass or the complete window? Are the drawn glazing bars decorative or glass-dividing? These are not formalities. They affect function, appearance, installation planning and comparability. Work through every item, mark uncertainties and give every supplier the same corrected version. This turns a planning document into a reliable basis for quotation requests.
Check before requesting a quote 1
Use the window schedule as a common benchmark
A sound enquiry starts with a simple rule: one item number should represent one clearly specified version. Item F-01 may occur several times where identical windows are planned in different rooms. In that case, the quantity and identical configuration must be unmistakable. If even one detail changes, such as the opening side, division, finish or glass, it will normally need its own item or an expressly documented variant note. Otherwise, one supplier may assume simplification while another prices every variation separately. The resulting quotes may have apparently comparable totals but different actual scope. Start by marking every line where a description could allow more than one version.
Keep all related documents beside the schedule: floor plans, elevations, sections, where applicable detail drawings, and a specification. The schedule often states what is to be supplied; drawings show where the element sits and its context. Do not silently reconcile conflicting information yourself. Note, for example, “F-08: schedule single-leaf, elevation double-leaf” rather than choosing a version independently. For refurbishment work, also record whether the schedule contains existing dimensions, design dimensions or order dimensions already checked on site. State which document must be reviewed if details conflict. This clarification belongs in the enquiry, not only at order confirmation.
Check item numbers, rooms and quantities
Start with a checklist: every item number should have a location, quantity, element description and traceable drawing reference. Room names are especially helpful for repeated sizes. A bathroom window may need different privacy, ventilation and operating features from a visually identical living-room window. Without a location, an item can be priced but important use requirements remain unresolved. Check whether doors are included in the same schedule. A patio door is easily grouped under “windows”, yet needs additional information on threshold, handle side and passage. Use unambiguous room names rather than changing abbreviations from different drawing revisions.
Check quantities not only line by line, but also by building side and floor. This can reveal elements missing from an elevation or counted twice. Identical windows on different façades may share an item provided every feature is genuinely the same. If not, separate the items. For an enquiry, a single-leaf inward-opening window may describe a suitable product type, but it does not replace the specific dimensions, handing, glass, finish or hardware requirement. Always include the item number. A small subtotal for each floor also makes it easier to compare the quote, order confirmation and actual delivered scope later.
Check before requesting a quote 2
Put dimensions in context before comparing
Numbers without a dimensional reference are a frequent source of misunderstanding. Width times height may mean outer frame size, opening size, structural opening or clear opening. The notation 1,235 × 1,485 mm does not explain this reference. For each group of items, ask: which dimension is shown, from which side is it read, and is it a design dimension or one verified on site? For windows with side fixed lights, toplights or coupled sections, also clarify whether the number denotes the overall size or individual parts. Record whether the order is consistently width × height so rotated dimensions do not pass unnoticed.
Do not copy dimensions uncritically from a façade elevation where the window schedule gives different values. Elevations may be simplified for design purposes, while a schedule may contain a transposed number. Check slopes, arches and special shapes particularly carefully. A triangular or sloping fixed-glazed window is defined by its outline geometry; width and height alone do not fully describe it. For such items, request a dimensioned sketch with clear reference points and the position of the slope. Connection details and the intended position of the element within the wall build-up are also part of installation planning. The responsible design professional should assess these points for the actual installation situation.
Read view, opening type and handing accurately
A window symbol does not always explain everything. First establish whether the drawing is read from inside or outside. Only then can left or right handing be assigned reliably. For certainty, also state in words which side the hinges are on in the stated view and the direction in which the sash opens. A tilt-and-turn window also needs its intended operating function. For a double-leaf version, record which sash carries the handle, which opens first and what division is intended. If the floor plan and window elevation use different viewing directions, label both clearly instead of relying on arrows alone.
The opening type must suit use of the room, not simply the façade drawing. An inward-opening sash can clash with furniture, curtains, fittings or a worktop. An outward-opening sash, by contrast, needs sufficient clear space outside. A two-leaf inward-opening window describes the basic opening direction and number of sashes, but does not automatically answer every detail. Mark possible conflicts for each relevant element in the floor plan and furniture layout. Also ask whether fixed and movable fields are clearly labelled. A visible division does not reliably show which field opens or which sash is used first in daily life.
Check before requesting a quote 3
Do not confuse fixed glazing with a fixed sash
A window schedule should clearly distinguish fixed glazing from an openable sash. A fixed-glazed element is intended as a non-opening part; it may provide daylight, views or a calm façade division. A movable sash additionally serves operation and ventilation. Where a room has only fixed glazing, the planned ventilation method should therefore be raised as a project question. It must not be replaced by assuming that a field will “probably open somehow”. Also check access for cleaning and maintenance from the planned installation position. For high-level or externally inaccessible fields, this practical question can influence the chosen arrangement.
For combined elements, a field sketch is particularly useful. Mark, for example, a fixed light on the left, an opening sash in the centre and another fixed light on the right. Add division dimensions or explicitly state when the supplier should propose them as an alternative. This prevents pricing only the outside overall width while interpreting the internal arrangement differently. For a wholly non-opening version, the appropriate category is a fixed-glazed window. Still check the actual schedule for mullions, transoms, division dimensions and glazing bars. For round or arched windows, it should likewise be clear whether the entire shape is fixed glazed or whether adjacent rectangular areas are planned as movable.
Compare glazing and U-values on the same basis
Terms such as double or triple glazing are a starting point, not a complete basis for comparison. Record in the enquiry which glazing is intended for each item and which additional properties are expressly required, such as privacy, patterned glass or a particular safety specification. A blanket statement for “all windows” is risky if individual rooms or door panels are planned differently. Create a separate glass column and have unclear requirements confirmed. For patterned glass, its designation, required appearance and assignment to the field should also be unambiguous. Always check quotations by item: special glazing may have been included for only one line although the summary sounds more general.
The reference basis must be stated for a U-value. A value for glazing is not automatically the value of the complete window. Ask: which value is provided, to which specific element and dimensions does it relate, and does it genuinely apply to every quoted item? A Super Low Uw passive-house window, outward-opening names a product configuration, but does not replace an item-specific confirmation of the required version and values. Do not compare a single figure alone. Dimensions, frame proportion, opening sashes, divisions and glazing all affect assessment of the actual element. If suppliers use different reference bases or sample dimensions, request an explanation before ranking them. Energy planning for the whole building should be handled by qualified professionals.
Check before requesting a quote 4
Describe glazing bars precisely, not only with an image
“With glazing bars” is too vague for an enquiry. Bars change a window’s appearance but can be made in different ways. Decorative bars are referred to as glazing bars. Glass-dividing bars genuinely divide the glazing and must be expressly described as glass-dividing bars. Also specify number, orientation, position and grid, for example two horizontal bars in the upper section. An elevation image is useful but must not replace the written specification. For asymmetrical divisions, give dimensions or traceable reference lines. If the grid must align across several elements, that design intention must be visible in elevations and jointly described for the affected items.
Check the bar layout separately for fixed lights and opening sashes. What appears symmetrical across the complete window elevation may finish differently at sash edges, mullions or transoms. Where a historic design is intended, frame effect, sash division and bar pattern must be assessed together. A historic-style two-leaf outward-opening casement window may provide a starting point, but the actual bar arrangement remains a separate specification. Also ask whether drawing and description show the same number. If no bars are wanted, write “without glazing bars” explicitly. This avoids a schematic illustration being treated as a binding division, or a decorative version being quoted when glass-dividing bars were intended.
Record doors fully as separate items
External doors and patio doors usually need more context in a window schedule than a standard window. Alongside width, height, opening direction and handing, clarify the relationship to the finished floor build-up, intended passage and handle side. For a terrace door, the threshold may be crucial to use, but its specific construction must not be inferred from a symbol. Record this as a question and coordinate it with connection and floor planning. A door leaf with a side panel is not a simple individual dimension but an assembly. Clearly state its overall width, division, fixed and movable areas, and the position of the side panel.
Large openings require particularly clear identification of movable and fixed parts. For Patio Life lift-and-slide doors the schedule should show, for example, which fields are fixed and which move, from which internal view the operating side is defined, and whether the dimensions apply to the complete unit. Add the required opening side in words and check whether furniture, an external step or an adjoining wall affects use. The same applies to folding or multi-leaf solutions. Request an item-specific drawing if the floor plan does not clearly show the travel direction. This ensures all suppliers price the same system and the desired passage does not end up on the wrong side because the view was misunderstood.
Check before requesting a quote 5
Assign finishes, handles and accessories explicitly
A window schedule is ready for enquiry only when visible and operable details are not confined to general notes. Check the required colour or finish inside and outside where these sides are to differ. Assign handles, hardware finishes, ventilation accessories, window sills, roller shutters or other components to clear item numbers. If certain parts are not to be included in supply, that can also be recorded as an exclusion. Where choices are missing, request separately priced alternatives rather than allowing the supplier free selection. This keeps the basic version comparable. Also check whether a global colour statement truly applies to special shapes, doors and differently designed interior rooms, or whether exceptions need their own lines.
Operating height and accessibility also deserve a look at the floor plan and section. A high-level window may be planned as a top-hung outward-opening window but the enquiry must specify its operating method and required actuation. For difficult-to-reach positions, ask how the element is intended to be operated day to day rather than defining only its form. Also record whether insect screens, privacy screening or solar shading need coordination. Such components are not automatically included in a window quotation, but may affect space, operation and connections. List separately what is to be quoted, merely prepared for, or planned by another trade. This prevents missing ancillary work from becoming visible only after price comparison.
Turn unclear details into a quotation matrix
Instead of sending several emails with isolated corrections, prepare a compact quotation matrix. Each line should contain item number, room, quantity, dimensional reference, element type, opening type, view or handing, glass, bars, finish and an open decision. Add a column headed “supplier to confirm”. Use it for specific questions such as “dimension understood as outer frame size?” or “bars priced as decorative or glass-dividing?”. Another column can refer to the governing drawing and its revision. The matrix does not replace a drawing, but shows which details are binding and which remain open. Send every supplier the same dated version. When questions are answered later, issue a new revision rather than overwriting individual cells without a change note.
Request feedback not only as a total, but item by item. On receipt, check that every item is included, quantities and dimensions have been adopted, and alternatives are separately identifiable. A lower quote is not automatically cheaper if an opening type, side panel, accessory or required glazing is missing. Compare scope first and prices second. For deviations, ask for an understandable list rather than a lump-sum price adjustment. Windows and doors from Bloomcabin have a five-year manufacturer guarantee. Delivery takes 4–6 weeks, subject to order confirmation. Still check the specific order confirmation line by line against the final window schedule and document approved changes.
Frequently asked questions
What is the main difference between a window schedule and a window drawing?
A window schedule structures item numbers, quantities and properties. A drawing shows location, view, shape or installation situation. You need both for a reliable enquiry: the schedule creates comparability, while the drawing clarifies spatial relationships and divisions. Conflicts should be resolved in writing before requesting quotations and assigned to a clearly identified drawing revision.
Must I state left or right handing?
The information can help, but may not be enough on its own. Also name the viewing side, for example the internal view, and describe hinge side and opening direction in words. For double-leaf windows, the handle side, first-operated sash and intended use should also be clear from the schedule or field sketch.
Is it enough to state width and height in millimetres?
No. The supplier must know what the dimensions refer to, such as outer frame size, structural opening or clear opening. Special shapes also need dimensioned geometry. State whether dimensions are design dimensions or already checked on site, and whether the order consistently reads width × height.
How should I describe glazing bars in an enquiry?
First identify the type: glazing bars for a decorative version, or glass-dividing bars for genuinely separate glass panes. Add their number, horizontal and vertical position, grid and assignment to a fixed light or sash. If no division is wanted, write “without glazing bars” clearly in every affected item.
What should I do if not every detail has been decided?
Separate fixed requirements from open decisions. For open points, request clearly marked alternatives instead of silent assumptions. Have the basic version priced fully and item by item. You can then compare variants later without retrospectively aligning the scope of several quotes or trying to unravel unclear lump-sum prices.
Next step
A window schedule is effective not because it contains many abbreviations, but because every item can be understood without guesswork. First check quantity, location, drawing revision and dimensional reference. Then clarify opening type, handing, fixed and movable fields, glazing and bars. Add finishes, operation and accessories only with clear assignment. A short, visible list of open questions is more valuable than apparent completeness. When every supplier receives the same version-controlled documents and identifies deviations item by item, scope and alternatives can be compared purposefully. Approve the specification only when the window schedule, drawings and order confirmation match.
