Description
McAlpine Shallow Shower Trap — 90mm — 53mm Height — 25mm Seal — ST90CPB-S-53
The McAlpine ST90CPB-S-53 is an ultra-low profile shallow shower trap engineered for installations where sub-floor clearance is severely restricted. At just 53mm overall height, it is one of the slimmest 90mm shower traps available whilst maintaining a 34 litre/min flow rate and full BS EN 274 compliance. The polypropylene body is supplied with a removable 110mm chrome plated brass flange and all fittings for a complete installation. Ideal for timber floor constructions, retrofit projects, and first-floor bathrooms with minimal joist depth.
⚠️ Check clearance before ordering. This trap requires
53mm of clearance beneath the shower tray. Confirm your sub-floor depth before purchasing. Note: this trap has a
25mm water seal — if you require a deeper 50mm seal for better odour protection, see the
McAlpine ST90CPB-S-70 (70mm height, 50mm seal).
Key Features
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53mm overall height — one of the slimmest 90mm shower traps available; suits severely restricted sub-floor depths
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25mm water seal — meets minimum UK building regulation requirement for odour protection
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34 litres/min flow rate — high drainage performance; prevents water pooling
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90mm waste hole — fits standard shower trays with 90mm waste apertures
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1½″ BSP thread — standard UK connection size
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Removable 110mm flange — chrome plated brass; easy cleaning and debris removal
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1½″ solvent weld outlet — secure, leak-free connection to waste pipe
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Complete installation kit — 135° bend, BSP coupling nut, and 1½″ universal connector included
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BS EN 274 compliant — tested to BS EN 274-1:2002 and BS EN 274-2:2002
Technical Specification
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Brand: McAlpine
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Model: ST90CPB-S-53
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SKU: ST90CPB-S-53
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EAN: 5013512012530
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Type: Shallow shower trap
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Waste hole diameter: 90mm
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Overall height: 53mm
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Under-tray clearance required: 53mm
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Water seal depth: 25mm
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Flow rate: 34 litres/min (tested under 15mm constant head, BS EN 274-2:2002)
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Thread size: 1½″ BSP
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Outlet: 1½″ solvent weld
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Flange diameter: 110mm (removable)
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Flange finish: Chrome plated brass
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Body material: Polypropylene
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Weight: 0.3kg
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Standards: BS EN 274-1:2002 & BS EN 274-2:2002
What’s Included
- McAlpine ST90CPB-S-53 shallow shower trap body
- 110mm chrome plated brass removable flange
- 135° bend
- BSP coupling nut
- 1½″ universal connector
- Installation instructions
Suitable For
- Installations with severely restricted sub-floor clearance (as little as 53mm)
- Timber floor constructions and first-floor bathrooms with minimal joist depth
- Retrofit shower installations in existing bathrooms
- Wet room conversions with shallow floor build-ups
- Apartment and flat renovations with concrete floors
- Any installation requiring a 90mm waste hole trap with minimal height
Also Available — McAlpine Shallow Shower Traps
Coordinate Your Shower Installation
Frequently Asked Questions
What clearance does this trap require beneath the shower tray?
The McAlpine ST90CPB-S-53 has an overall height of 53mm and requires 53mm of clearance beneath the shower tray. This makes it one of the slimmest 90mm shower traps available and suitable for installations where even the ST90CPB-S-70 (70mm) would not fit. Measure the available depth between the underside of your shower tray and the floor before ordering.
What is the difference between the ST90CPB-S-53 and the ST90CPB-S-70?
Both are McAlpine 90mm shallow shower traps with the same 34L/min flow rate and BS EN 274 compliance. The key differences are height and water seal depth. The ST90CPB-S-53 (this product) is 53mm high with a 25mm water seal — the slimmest option, suitable for the most restricted installations. The ST90CPB-S-70 is 70mm high with a superior 50mm water seal — better odour protection, recommended where 70mm clearance is available. If you have the space, the ST90CPB-S-70 is the preferred choice for its deeper seal.
What size waste hole does this trap fit?
This trap is designed for shower trays with a 90mm waste hole and a 1½″ BSP thread. This is the standard waste hole size for the majority of UK shower trays. Check your tray specification before ordering if you are unsure.
What is the water seal depth?
The water seal depth is 25mm — the minimum required by UK building regulations. The water seal is the depth of water retained in the trap that prevents sewer gases from entering the bathroom. If you have sufficient clearance (70mm), the ST90CPB-S-70 with its 50mm seal provides significantly better odour protection and is less likely to evaporate in infrequently used showers.
What type of outlet connection does this trap use?
The outlet is 1½″ solvent weld, connecting to standard 40mm (1½″) solvent weld waste pipe. A 135° bend, BSP coupling nut, and 1½″ universal connector are included to allow flexible pipe routing beneath the tray.
Is this trap BS EN 274 compliant?
Yes — the McAlpine ST90CPB-S-53 is fully compliant with BS EN 274-1:2002 (requirements) and BS EN 274-2:2002 (test methods), the relevant British and European standard for sanitary waste fittings.
Can I order if the item shows as out of stock?
Yes — this product is available to order even when stock shows as zero. Please allow additional lead time and contact us at customerservice@bubblegumbathrooms.co.uk for availability.
