Wholesale Doors & Windows Suppliers

Sizes, standards and handing

Doors and windows follow regional sizing conventions that differ between countries, so product made to one standard may not fit openings built to another. Confirm the exact dimensions, the frame size versus the opening size, and the swing direction, called handing. Many are made to order, which means long lead times, no easy returns and a strict check of the specification before approval. A wrong measurement is typically the buyer's cost, not the supplier's.

Materials and construction

Frames come in uPVC, aluminium, timber and composite, and each has trade-offs in cost, maintenance, appearance and thermal behaviour. Timber needs finishing and upkeep, aluminium conducts heat unless it has a thermal break, and uPVC varies in quality between profiles. Glazing may be double or triple, with coatings and gas fills that affect insulation. Check the hardware, such as hinges, locks and handles, because poor hardware causes many complaints.

Performance and regulation

Building rules in many markets set limits on heat loss, expressed as a U-value, and windows may need to carry performance labels or declarations. Security-rated doors and windows, fire-resistant doors and safety glazing near floors and doors are regulated in many places. Fire doors are certified as a complete assembly including frame, seals and hardware, so swapping parts can invalidate the rating. Check the rules for your market, and ask suppliers for test evidence rather than relying on descriptions.

Transport and handling

Glass, frames and finished surfaces are easily damaged. Ask about packaging, how units are racked and whether goods are inspected before dispatch. Check on delivery and note damage on the paperwork immediately, because hidden damage claims become difficult once units are installed. Store units upright, dry and protected from sun and moisture. Interior doors can warp if left flat in damp conditions.

Margins, ranges and seasonality

Standard-size stock products move faster and carry lower margins than bespoke ones, which offer higher margins but longer waits and more risk. Demand rises with renovation and building activity, often in warmer months in many regions, and lead times lengthen when orders peak. Order early for projects with fixed dates.

Questions to ask a supplier

• What are the exact dimensions, handing and tolerances?
• What is the U-value, and what test documents do you hold?
• Is the glazing safety rated where required?
• Is the fire or security rating certified for the whole assembly?
• What is the lead time and the cancellation policy for made-to-order items?
• How is it packed, and how are damage claims handled?

Be sceptical of performance claims that are not backed by test reports.