Description
Atlas Hoter U White 25 kg is the white-cement, fibre-reinforced 2-in-1 EPS and XPS adhesive and basecoat that bonds insulation boards and embeds fibreglass mesh in one product, delivering ≥ 0.25 MPa adhesion to concrete and a 4-hour pot life — with a bright cured surface that lets pale silicone and acrylic renders go on over a single light primer pass instead of two coats of tinted product. Sold within the professional EPS adhesives and basecoats range at Renders World, this is the specification UK installers reach for when the decorative coat is white, off-white, pastel, or any light shade where grey show-through would force a heavier primer stage.
Where Atlas Hoter U White Performs Best — Light-Finish EWI Build-Ups
Atlas Hoter U White 25 kg is a cement-based 2-in-1 mortar engineered for the same EPS, graphite EPS, and XPS bonding and mesh-reinforcement duty as the Grey version, but built on a premium white-cement binder that cures to a bright basecoat surface. On a light-render elevation — pale silicone, off-white acrylic, or any cool-toned thin coat under 1.5 mm grain — one regular primer pass replaces the two coats of opaque tinted primer a grey base would demand.
The product belongs on facades where the finish-coat colour is decided upstream of the basecoat order: new-build pale renders, conservation-zone whites and creams, and refurbishment projects where the specifier or homeowner has already locked in a light decorative scheme. On graphite EPS boards specifically, the white basecoat also reduces the visual contrast between adhesive and board if a coat is ever damaged in service, making maintenance touch-ups less visible against the finished elevation.
Why Trade Specifiers Choose Atlas Hoter U White
- One primer pass under pale finishes: The white-cement basecoat lets a standard quartz primer cover in a single coat, saving the second tinted-primer pass that a grey base requires under light renders — a measurable programme and material gain on every elevation.
- Brighter, truer top-coat colour: Pale silicone and acrylic renders sit on a white substrate without the cool grey cast that pulls warm tones toward khaki — important on heritage creams, conservation whites, and Scandinavian-influenced new-build palettes.
- 3D microfibre crack control: Structural microfibres distribute thermal and mechanical stress across the cured layer, holding the basecoat together against hairline cracking. The fibre-enhanced basecoats guide covers why this matters across the elevation life.
- 4-hour pot life at 20 °C: Mixed mortar stays workable for around four hours — identical to the Grey variant — so a two-person team can batch-mix at the station and apply long stretches of basecoat without restarting at the mixer every 90 minutes.
- ≥ 0.25 MPa adhesion to concrete, ≥ 0.08 MPa to EPS: Tested bond strength on both mineral substrates and board surfaces supports certified Atlas ETICS detailing on UK jobs where Building Control and warranty providers verify the spec.
- Lower quartz primer consumption: The smooth fibre-reinforced finish under the trowel pulls primer evenly without thirsty patches, reducing primer use on the next stage by a measurable margin on long runs.
Technical Specifications — Atlas Hoter U White Data Sheet Highlights
| Property | Value |
|---|---|
| Product type | White-cement 2-in-1 adhesive and reinforcing mortar |
| Composition | White cement, mineral fillers, polymer modifiers, microfibres |
| Pack size | 25 kg bag |
| Colour | White (premium white-cement binder) |
| Mixing ratio | 5.0–5.5 L clean water per 25 kg |
| Pot life | ~ 4 hours at 20 °C |
| Open time | Min. 25 minutes |
| Application temperature | +5 °C to +25 °C (substrate and ambient) |
| Consumption — board fixing | 4.0–5.0 kg/m² (≈ 5 m² per bag) |
| Consumption — basecoat and mesh | 3.0–3.5 kg/m² (≈ 7 m² per bag) |
| Reinforced layer thickness | 2–5 mm |
| Adhesion to concrete | ≥ 0.25 MPa |
| Adhesion to EPS | ≥ 0.08 MPa |
| Standards | EN 15824:2017 · ETA-certified within Atlas ETICS |
| Application | Hand trowel or rendering machine |
| Shelf life | 12 months, sealed, dry storage |
How to Apply Atlas Hoter U White — Mixing, Mesh Embedding, and Primer Workflow
Mix the 25 kg bag into 5.0–5.5 litres of cool, clean water with a paddle mixer on low speed until lump-free, rest the paste for five minutes, then briefly remix to activate the polymers. For board fixing, apply the mortar in a 3–4 cm perimeter band with three to six central dots, then press the board against the wall until adhesive contact covers at least 40 % of the rear face — the figure that satisfies the certified Atlas ETICS detail.
After the bonding layer has cured (typically 24 hours) and mechanical fixings are installed, trowel a 2–3 mm continuous basecoat, press Atlas 150 g/m² fibreglass mesh into the wet mortar with minimum 100 mm overlaps, and smooth a second thin pass over the top so the mesh sits in the outer third of the layer. The complete basecoat and mesh reinforcement layer guide covers overlap discipline, corner detailing, and the diagonal mesh patches around openings.
Once the basecoat is fully cured, the white-cement surface accepts a single light pass of standard quartz primer rather than the two tinted-primer coats that grey bases need under pale renders — this is the workflow gain that pays back the upgrade to the white variant on light-finish elevations.
Installation Notes — Conditions, Drying Times, Finishing
Atlas Hoter U White performs best between +5 °C and +25 °C, with both substrate and ambient temperatures inside that range for at least 24 hours after application. On dense, well-cured concrete the mortar bonds directly; on absorbent or dusting substrates such as aerated concrete or old lime renders, a coat of substrate primer evens out the suction so the adhesive cures at full strength across the elevation.
Schedule basecoat work for overcast conditions or shaded scaffolding where possible — direct midday sun on dark graphite EPS can flash-dry the thin mortar layer before the mesh is properly embedded, weakening the bond between mortar and fibre. Allow the finished basecoat to cure for a minimum of three days before priming and applying the pale decorative render, extending that window in cool or humid weather so the white surface is fully ready to receive the lighter primer regime that justifies the variant choice in the first place.
Pro Tips From UK Installers Using Atlas Hoter U White
- Protect the white surface from boot tracks. The bright basecoat shows boot soles, scaffolding scuffs, and tool drag more than grey — drop dust sheets at the base of each elevation before the basecoat day starts, not after the first mark appears.
- Use the long pot life as a logistics tool. The four-hour window suits batch mixing on light-render jobs of 200 m² and above; one operative trowels continuously while another preps the next bay, with no waste from mortar stiffening in the bucket.
- Watch the wet edge, not the clock. The 25-minute open time governs how long you have to embed the mesh — losing the wet edge is the most common cause of mesh telegraphing through the finish, which on white renders shows up under raking light far sooner than on dark coats.
- Order primer to white coverage rates. Calculate primer consumption against the single-coat rate the white basecoat enables, not the double-coat rate quoted for grey jobs — overordering primer for a white-basecoat elevation is the most common material waste on light-render projects.
Is Atlas Hoter U White Right for Your Project?
- Atlas Hoter U White is the right call when your decorative coat is white, off-white, pastel, or any light shade, and you want to save the second tinted-primer pass that a grey base would force on the next stage of the build.
- Mid- or dark-tone finish coat? The grey-cement sibling Atlas Hoter U Grey 25 kg delivers identical 4-hour pot life and ETA-certified bond strength at a lower price point — the better economic choice when grey show-through is invisible under the finish.
- Insulating with mineral wool? Mineral wool needs a more vapour-permeable adhesive engineered for the slab structure — Roker U Grey 25 kg is the wool-and-EPS-rated alternative within the same range.
- For a full white-finish specification, pair Atlas Hoter U White with the EPS insulation boards range as the thermal layer, then a single-pass quartz primer and a pale silicone thin-coat render from the Atlas decorative line. Staying inside one certified ecosystem protects warranty cover on the finished facade.
FAQ — Atlas Hoter U White Coverage, Compatibility, Ordering
How many bags of Atlas Hoter U White do I need per 100 m² of EWI?
At average rates of 4.5 kg/m² for board fixing and 3.5 kg/m² for the basecoat, a 100 m² elevation consumes around 450 kg + 350 kg = 800 kg of mortar, which works out to 32 bags. Order 35 bags per 100 m² to absorb the 10 % wastage that typically comes with uneven substrates, complex window detailing, and offcut losses on long basecoat runs.
When is the white version worth the upgrade over Hoter U Grey?
Choose white whenever the decorative finish is light enough that grey show-through would force a tinted primer regime — pale silicone, off-white acrylic, conservation creams, and pastel schemes all benefit. On mid-tone and dark-tone finishes the grey sibling is the cost-effective spec, since the white-cement advantage delivers no workflow gain under a deep colour. The EPS adhesive selection guide walks through how finish-coat colour shapes adhesive choice across the build-up.
Can I skip the primer entirely under a pale render on the white basecoat?
The white surface removes the colour-masking role of the primer, but a standard manufacturer-approved primer is still recommended to equalise substrate suction before the silicone or acrylic topcoat goes on. The workflow gain is moving from two tinted-primer coats to one regular pass — not from one coat to none.
Do I still need mechanical fixings if the adhesive is this strong?
Yes — certified ETICS installations in the UK rely on mechanical anchors to manage wind-load pressures and long-term structural movement, regardless of adhesive grade or colour. Install the fixings through the boards after the bonding layer has fully cured (typically 24 hours minimum), then apply the reinforced basecoat over the anchor heads so they are fully encapsulated within the white layer.
How long does the mixed mortar stay workable?
At 20 °C the mixed paste stays workable for approximately four hours — identical to the grey variant. Plan batch sizes around that window: a two-person team can comfortably mix 50 kg at a time on warm summer days and still finish the bucket before the mortar starts to stiffen, keeping pace with the larger primer-saving runs that white-basecoat projects favour.
How long can I store unopened bags on site?
Sealed bags keep for 12 months from the manufacture date when stored off the ground in dry conditions, ideally on a pallet under a weather sheet rather than directly on bare concrete. Once a bag is opened, transfer any unused powder into a sealed plastic tub the same day — humid UK air will reduce the pot life and bond strength of partially used bags within a week.
Technical Documentation — Atlas Hoter U White TDS and DoP
- Atlas Hoter U White — Manufacturer Technical Data Sheet (PDF, atlas.com.pl)
- Atlas Hoter U — Product Page and Declaration of Performance (atlas.com.pl)