A mattress topper cut to size UK enquiry usually involves an older bed, caravan, motorhome, boat, campervan, antique frame or handmade sleeping platform that does not match a standard rectangle. The most important part of the order is not the foam choice. It is an accurate, unambiguous set of finished dimensions.
The All Foam topper page prices Single, Double, King Size and Super King products online. A non standard width, length or shape is not available through the standard selector and must be discussed with the team before ordering.
This guide explains how to measure a custom topper, when to use a template and why orientation, access and the condition of the mattress underneath all matter.
Confirm that a topper is the right product
A topper changes the upper comfort layer of an existing mattress. It should sit on a level, supportive and structurally sound surface.
Do not order a custom topper to hide a permanent hollow, broken spring, collapsed foam core or damaged bed base. The new foam follows the surface below it. If that surface dips or slopes, the topper usually follows the same shape.
Inspect the mattress without bedding. Check the edges, centre, seams and areas beneath each sleeper. Then inspect the frame or platform. The mattress topper or new mattress guide helps separate a comfort problem from structural failure.
Start with standard UK sizes
The current All Foam topper range uses these listed dimensions:
- Single: 90cm by 190cm.
- Double: 135cm by 190cm.
- King Size: 150cm by 198cm.
- Super King: 180cm by 198cm.
If the existing mattress matches one of these sizes and has square corners, use the standard product selector. A small difference should still be measured carefully because an older mattress can change shape through use.
Do not order by the label sewn into the old mattress alone. Measure the actual sleeping surface and compare it with the exact listed dimensions.
Measure the mattress, not only the frame
A topper needs to match the top surface of the mattress. The frame can be larger, smaller or shaped differently around it.
Remove bedding and measure the mattress width at the head, middle and foot. Measure length on both sides and through the centre. Record the smallest and largest figures if they differ.
For a straight rectangular mattress, the finished topper normally follows the mattress dimensions. For a mattress with rounded corners, tapers or cut outs, a drawing or template is needed.
Use centimetres unless All Foam asks for another unit. Write the unit beside every number so there is no ambiguity.
Record orientation clearly
Odd shapes can be produced as a mirror image if left and right are not marked.
Draw the topper as viewed from above. Mark:
- Head and foot.
- Left and right as you lie on the bed.
- The side facing upwards.
- Walls, doors, wheel arches or furniture beside the sleeping area.
- Any zip, hinge or fold line in the existing mattress.
Add an arrow showing the direction of the bed. A photograph can support the drawing, but it should not replace dimensions.
How to measure a tapered bed
A tapered bed is wider at one end than the other. Measuring only the maximum width and total length does not define the side angles.
Record the width at the head and foot, then measure at several fixed distances along the length. For example, record the width every 25cm or at each obvious change in shape. Mark the distance of each width measurement from the head.
Measure both side lengths as well. A bed that looks symmetrical may have one side longer or a different curve.
A full size template is often the safest method when the taper is irregular.
How to measure rounded corners
A rounded corner is difficult to describe with one radius unless the curve is a true part of a circle and the centre point is known.
Place paper or card over the corner and trace the exact edge of the mattress or platform. Mark where the template sits, which side faces up and which corner it represents.
If a full size template cannot be posted, take several measurements from fixed straight edges and send clear photographs with a scale. Ask All Foam whether the information is sufficient before production.
Do not guess a curve from a small photograph. Camera perspective can make the radius look different.
How to measure cut outs and wheel arches
A cut out needs its width, depth and exact position.
Measure the distance from the head or foot to the start of the cut out. Measure from the side edge to the nearest point. Record the width and depth of the opening and any rounded corners.
For a wheel arch or cabinet notch, check whether the topper needs to follow the full platform shape or only the mattress above it. Sometimes the existing mattress bridges a lower obstruction and the topper remains rectangular.
Mark the cut out on a top view drawing and include a template if the shape is complex.
Use a full size template for complicated shapes
A template is the most reliable way to describe a shape that includes curves, tapers and multiple cut outs.
Use strong paper, card or a joined sheet that lies flat. Fit it to the sleeping surface and trim it until it represents the finished topper shape. Do not use stretchy fabric because it can distort.
Write directly on the template:
- Customer name and order reference.
- Head, foot, left, right and top.
- Finished dimensions.
- Whether the line is the final cut line.
- Any split or hinge position.
Roll or fold the template only if this does not alter the shape. Ask the All Foam team how they want it supplied.
Decide whether the topper needs to be split
A large topper can be difficult to move through a caravan door, narrow stairway or boat hatch. A split design may make handling easier.
The split should be positioned where it causes the least disruption to comfort. It may follow a hinged bed section, centre join or existing mattress split.
Measure each piece separately and show how the edges meet. Mark whether the pieces are equal or different shapes. Consider whether a cover, protector or fitted sheet can hold the sections together.
Discuss access before production. Do not assume that a thick foam topper can always be rolled tightly enough to pass through an opening.
Choose the topper material and depth
The standard All Foam range gives a useful comparison of available materials.
The memory foam topper is available in 2.5cm, 5cm and 7cm. It responds gradually to heat and pressure and follows the body more closely.
The medium density foam topper is 5cm and gives a straightforward softer feel. The high density foam topper is 5cm and gives a firmer, more stable surface.
The Reflex Medium and Reflex Firm toppers are 5cm and recover more quickly than memory foam.
A custom size enquiry does not mean every material or depth can automatically be produced in every shape. Ask All Foam to confirm the available options.
Thickness affects more than comfort
A deeper topper raises the bed and may interfere with cupboards, window ledges, guard rails or folding furniture. It also needs deeper bedding.
In a caravan or boat, overhead clearance may be limited. Measure from the top of the existing mattress to the lowest obstruction and consider how the sleeping area is entered.
The mattress topper thickness guide compares 2.5cm, 5cm and 7cm choices in more detail.
Check bedding and covers
Standard fitted sheets may not match an unusual shape. A rectangular protector can sometimes be tucked around a shaped topper, but deep curves and cut outs may require a custom cover.
Decide whether the topper will be used beneath a fitted sheet, inside a zipped cover or under a mattress protector. Measure the combined mattress and topper depth.
Do not force a thick topper into bedding that pulls the corners or compresses the edges. This can make the topper move and can alter the surface feel.
Ventilation in caravans, motorhomes and boats
Compact sleeping spaces can collect condensation. A topper adds another layer above the mattress, so the complete setup needs air circulation.
Keep fixed vents clear. Lift and air bedding and foam when appropriate. Check the underside of the mattress and platform for damp. A new topper should not be placed over mould or persistent moisture.
In a boat or leisure vehicle, follow the manufacturer guidance for ventilation and safety. Do not block air gaps or equipment access with a larger topper.
Access and folding furniture
A sofa bed, dinette conversion or lifting bed has moving parts. Measure the sleeping surface when fully open and check the storage position.
A topper may need to be removed before the furniture is folded. Memory foam and other flexible foams should not remain tightly folded or compressed for long periods.
Check hinges, latches and support panels. The topper must not interfere with mechanisms or create a trapping hazard.
Custom products and returns
All Foam states that bespoke cut to order foam and other customised products cannot normally be exchanged or refunded when they are not damaged, defective or incorrect. Memory foam products also have hygiene related return restrictions.
This makes accurate measuring essential. Review the current delivery and returns policy and full terms before approving a custom order.
Check every dimension, orientation mark and material choice. A production team can follow the information supplied, but it cannot know that a measurement was taken from the wrong edge.
Common measuring mistakes
The first common mistake is providing only the maximum width and length for a shaped bed. Those two figures do not describe curves or tapers.
The second is forgetting orientation. A left hand cut out can become a right hand cut out if the drawing is viewed differently.
The third is measuring bedding instead of the actual mattress surface. Fabric stretches and does not define the foam shape accurately.
The fourth is subtracting an arbitrary allowance. The correct fit depends on the cover, frame and material. Ask All Foam what finished tolerance is appropriate.
The fifth is ignoring access. A perfect one piece topper is not useful if it cannot enter the room or fit around furniture.
Information to send with an enquiry
Provide the All Foam team with:
- The intended use and location.
- Exact finished width, length and depth.
- A top view drawing with orientation.
- A template for complex curves or cut outs.
- The existing mattress condition and size.
- Preferred foam type and feel.
- Required topper thickness.
- Access restrictions and any split preference.
- Photographs that support, but do not replace, the measurements.
Ask for written confirmation of the agreed shape and specification before production.
Final answer
A custom cut mattress topper begins with an accurate shape, not a guess. Measure the mattress surface in several places, mark head, foot, left, right and top, and use a full size template for curves, tapers and cut outs.
Confirm that the mattress underneath is still supportive. Choose the material and thickness only after the shape, bed height, bedding, ventilation and access have been checked.
Use the online topper page for the four standard UK sizes. Contact All Foam before ordering any non standard or odd shaped topper, and review the custom product return terms carefully.