On any active construction site, the humble mortar tub and builder's bucket are among the most hard-worked pieces of equipment you'll find. Reliable, durable mixing and carrying containers are essential for concrete, mortar, plaster, screed, and general site tasks. But not all tubs are created equal — choosing the wrong material, size, or construction can mean cracked tubs, wasted product, difficult cleaning, and unnecessary replacement costs.
This guide covers everything tradespeople, contractors, and site managers in the UK need to know when specifying mortar tubs and builder's buckets for construction sites.
What Are Mortar Tubs Used For?
Despite the name, mortar tubs are used for far more than mortar. On a typical UK construction site, you'll find them used for:
- Mixing mortar for brickwork and blockwork
- Mixing concrete for small pours and repairs
- Mixing plaster, render, and screed
- Soaking bricks before laying
- Carrying and storing aggregates, sand, and gravel
- Water storage for site use
- Waste collection — cutting debris, concrete splatter, off-cuts
- Temporary storage of tools and fixings
Materials: HDPE vs Rubber
HDPE (High-Density Polyethylene) Mortar Tubs
HDPE is the most common material for modern site mixing tubs. Its properties make it particularly well-suited to construction environments:
- High impact resistance: Won't crack when dropped or struck on site
- Chemical resistance: Withstands cement, lime, additives, and cleaning agents
- Smooth internal surface: Mortar and concrete are easily cleaned out
- Consistent wall thickness: Manufactured to tight tolerances
- Long service life: 5–10 years with normal site use
- UV stabilised: Maintains properties in outdoor storage
- Lightweight: Easy to manoeuvre, even when large
HDPE tubs are the standard choice for professional tradespeople and larger sites where consistent performance is expected.
Rubber Mortar Tubs
Traditional rubber tubs — moulded from recycled or virgin rubber — have been used on UK sites for generations. Their key advantage is flexibility:
- Flexible walls: Dried or set concrete can be cracked out by squeezing the tub — no chipping required
- Tough and abrasion-resistant: Handles rough aggregate mixing well
- Low noise: Rubber absorbs impact — quieter than plastic on site
- Cold weather performance: Remains flexible in freezing conditions unlike some plastics
The main drawback is weight — rubber tubs are significantly heavier than HDPE equivalents, making larger sizes harder to manoeuvre. They also degrade faster in UV-exposed outdoor storage.
Sizes: Choosing the Right Capacity
Small Tubs (30–60 litres)
Suitable for:
- Mixing small batches of tile adhesive, grout, or repair mortar
- Carrying water for cleaning or tool washing
- Storage of fixings, nails, and small materials
- Use in confined spaces and domestic renovation
Medium Tubs (100–150 litres)
The most versatile size range for UK sites:
- Standard bricklaying mortar mixing
- Concrete repair mixes
- Aggregate and sand storage
- Multi-purpose site tasks
A 100-litre HDPE mortar tub is the workhorse size found on most UK residential and commercial construction sites. It offers enough capacity for efficient working without becoming unwieldy when full.
Large Tubs (200 litres+)
Large tubs are specified for:
- High-output bricklaying gangs needing less-frequent refilling
- Soaking large quantities of bricks simultaneously
- Screed and render operations
- Water storage in areas without direct supply
Note: a full 200-litre tub of wet mortar weighs approximately 300–350 kg — never attempt to move a full large tub without mechanical assistance.
Handles, Lips, and Features
When evaluating site mixing tubs, pay attention to:
Handles
- Integral moulded handles: Most durable — no weak points from bolt-on fittings
- Rope handles: Common on budget tubs — can fray and fail under load
- Number of handles: 2–4 depending on size — two-person carry for larger tubs
Base Design
- Ribbed base: Adds stiffness to prevent bowing under load
- Flat base: Stable on level surfaces but may flex when heavily loaded
- Stackable design: Important for storage — properly profiled tubs should not lock together when stacked
Wall Thickness
Thicker walls mean greater strength and longer life. Check manufacturer specifications — budget tubs often use thinner material that cracks under the weight of dense aggregate mixes.
Cleaning and Maintenance
Proper cleaning dramatically extends the service life of mortar tubs:
- Clean immediately after use: Fresh mortar and concrete rinse out in minutes; set material requires significant effort or damages the tub
- Use a stiff brush and water: A purpose-made tub cleaning brush makes this quick
- Rubber tubs: Flex the walls after drying — any residual set material will crack and fall away
- Avoid metal scrapers on HDPE: Can scratch and create rough surfaces that encourage bonding of subsequent batches
- Storage: Store inverted or in a sheltered area — UV damage to rubber is greatly accelerated by direct sun exposure
How Many Tubs Do You Need?
A simple rule for estimating site requirements:
- One bricklayer: 2 mortar tubs (one in use, one mixing ahead)
- Two bricklayers: 3–4 tubs
- Large gang (4+ operatives): 6–8 tubs plus dedicated mixing area
Having adequate tubs prevents production bottlenecks — a bricklayer waiting for mortar is expensive lost time.
Browse our range of mortar tubs and builder's buckets at Barriers Co — including HDPE mixing tubs from 30 to 200 litres, rubber mortar tubs, and site bucket packs for UK trade and construction.
Frequently Asked Questions
What size mortar tub do I need for bricklaying?
A 100–150 litre tub is the standard choice for bricklaying. It holds enough mortar for efficient working while remaining manageable when mixing by hand or paddle mixer.
Is HDPE or rubber better for mortar tubs?
HDPE is generally preferred for durability, ease of cleaning, and light weight. Rubber is better if you frequently let mortar set in the tub — the flexible walls allow you to crack out set material easily.
Can you mix concrete in a mortar tub?
Yes — mortar tubs are regularly used for small concrete mixes. Choose an HDPE tub rated for construction use with a reinforced base and thick walls to handle the weight and abrasion of concrete aggregate.
How long do mortar tubs last on site?
A quality HDPE mortar tub should last 5–10 years with proper use and cleaning. Rubber tubs typically last 3–7 years before cracking becomes an issue.
Can mortar tubs be used for water storage?
Yes — HDPE mortar tubs are food-safe grade in most cases and fully suitable for clean water storage. Avoid storing water in rubber tubs long-term as some rubber compounds may leach into standing water.
What is the difference between a mortar tub and a mixing tray?
A mortar tub is a deep-sided container, typically with handles, designed for high-volume mixing and carrying. A mixing tray is a shallow, flat-bottomed rectangle used for hand mixing on the ground. Tubs are better for volume and transport; trays are better for working at ground level with a shovel.