The Manthorpe GRS-SE provides a neat, insulated entry point for a single radiator pipe through a wall. Slim enough to fit behind the radiator, it includes a rubber grommet and sealant channel to meet modern air leakage building regulations.
The Manthorpe GRS-SE single exit radiator pipe seal is designed to give one radiator pipe a clean, insulated passage through a wall while maintaining an airtight finish. It sounds like a small detail, and in some ways it is — but get it wrong and you have cold draughts, failed air-pressure tests, and an inspector with a clipboard giving you that look. The GRS-SE keeps all of that at bay.
The unit is slim by design, sitting comfortably behind the radiator panel without fouling the brackets or the radiator body itself. It works with radiators that use a third, central bracket, and its face-fix nature makes it well suited to st wall constructions where recessing is not an option. It can be orientated in any direction, which takes the hassle out of pipe alignment when the pipework refuses to cooperate — as pipework tends to do.
Where the Manthorpe GRS-SE Single Exit Radiator Pipe Seal Earns Its Keep
The obvious application is straightforward single-pipe radiator connections, but the GRS-SE becomes particularly useful on larger radiators where the pipework drops from a central point and risks sagging below the bottom of the radiator. In that situation, two GRS-SE units used together provide twin entry points that follow the actual pipe positions rather than forcing the pipe run to conform to a single central exit. Neat, practical, and it keeps the job looking deliberate rather than improvised.
A rubber grommet grips the pipe securely and prevents air escaping around it. On the reverse face, a sealant channel lets you bed the unit down properly against the wall surface, forming a continuous seal. The convex profile of the fitting helps maintain contact even on slightly uneven plaster or board, adding a further layer of confidence that the air-tightness target will be met. Two fixing points, offset from the pipe penetration itself, hold it firmly without putting stress through the wall opening.
For any new-build or refurbishment work where Part L compliance is on the checklist, the manthorpe single exit radiator pipe seal is one of those fittings that does exactly what is needed without requiring any thought once it is in. And at this price, there is no reason to improvise with a blob of silicone and hope for the best.
Pro Tip: When fitting two GRS-SE units on a larger radiator, mark both pipe centres on the wall before you fix either plate, then check the spacing matches your radiator valve centres before drilling — saves the awkward conversation about why the radiator now hangs at a slight angle.
The GRS-SE is used by plumbers and heating engineers on both new-build and renovation projects wherever radiator pipework needs to pass cleanly through a finished wall surface. It suits timber-frame and studwork construction particularly well given its face-fix design, and it is commonly specified on projects where building regulations require demonstrable air-tightness at service penetrations. It sees regular use in domestic properties, apartments, and light commercial buildings where modern Part L compliance is a requirement.
New-build and refurbishment projects requiring air-tightness
Works With
Standard 15mm radiator pipework
Face-fix wall surfaces including plasterboard
Paired GRS-SE for twin-pipe radiator arrangements
Wall sealant in integral sealant channel
Key Features
Rubber grommet secures pipe and prevents air loss
Sealant channel on reverse face for airtight installation
Convex face profile aids seal on uneven wall surfaces
Two fixing points offset from the pipe penetration
Orientates in any direction to suit pipe alignment
Slim profile fits behind radiator panel
Not suitable for: Not suitable for use as a dual exit fitting on its own — a second GRS-SE unit is required for twin-pipe installations. Not intended for pipework passing through external walls or structural masonry where a separate fire-stopping or cavity sleeve solution is required.
Mark the pipe centre position on the wall and drill or cut the required hole for the pipe to pass through cleanly. Apply sealant into the channel on the reverse face of the GRS-SE before offering it up to the wall. Orientate the fitting in whichever direction best suits your pipe run, then fix it using the two offset fixing points — screws into plasterboard plugs or direct into timber noggins depending on the wall construction.
Feed the pipe through the rubber grommet, which will grip it and close off any remaining air gap around the pipe. Check the fitting sits flush and the sealant has fully bedded before finishing. For larger radiators needing two pipe entries, fit the second GRS-SE in the same way, ensuring both are positioned to match the valve centres of the radiator before committing to fixings.
Mark the pipe centre position accurately on the wall surface
Drill or cut the pipe penetration hole to the correct diameter
Apply sealant into the channel on the reverse face of the fitting
Orientate the GRS-SE to suit your pipe direction and offer it up to the wall
Fix using the two offset fixing points with appropriate fixings for the wall type
Feed the radiator pipe through the rubber grommet until it seats securely
Check the fitting sits flush and the seal is continuous before finishing the wall surface
Can I use a single GRS-SE for a radiator with two pipe connections?
No. The GRS-SE is a single exit fitting and handles one pipe only. For a standard radiator with two pipe connections you will need two GRS-SE units. This pairing is also the recommended approach for larger radiators where a central pipe run would sag below the radiator bottom — using two units lets you position each seal directly at the actual pipe location.
Does the GRS-SE meet current building regulations for air leakage?
Yes. The GRS-SE is designed specifically to address the air leakage requirements of modern building regulations. The rubber grommet, sealant channel on the reverse face, and convex profile work together to provide a proper air-tight seal at the pipe penetration point, helping your installation pass air-pressure testing.
The Manthorpe GRS-SE is a face-fix pipe seal plate manufactured from rigid plastic with a convex front profile to maintain contact against wall surfaces that are not perfectly flat. The rubber grommet insert creates a compression seal around the pipe, and the integral sealant channel on the reverse face allows the perimeter of the fitting to be fully bedded in sealant for a continuous air barrier. Fixing is via two points positioned clear of the pipe penetration to avoid stress cracking around the opening.
Product Code
GRS-SE
Brand
Manthorpe
Exit Type
Single
Fix Type
Face fix
Grommet Material
Rubber
Sealant Channel
Yes, integral on reverse face
Orientation
Any direction
Fixing Points
2, offset from penetration
Compatible Wall Types
Plasterboard, studwork, masonry
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