Uzin, United Kingdom: Installing floors in conservatories or solar gain

What adhesive should be used to install floors in areas with high solar gain?

Installing Floors in High Solar Gain Areas: Adhesive Choice, Application Method and Best Practice

During the warmer months, certain types of floor coverings installed in specific areas of buildings with large glass surfaces can be pushed to their limits. South-facing installations in conservatories, shopfronts and areas with bi-fold doors can experience significant floor-covering surface heating via solar gain through the glazed panels. This heating and subsequent cooling can lead to expansion and contraction in materials such as luxury vinyl tiles (LVT), vinyl and rubber floor coverings.

If the wrong adhesive is selected or an incorrect application method is used, it may lead to negative results, including:

Curling or tenting of LVT planks and tiles
Debonding near windows and doors
Gapping at joints as the floor covering contracts
Visible movement and premature failure

To keep flooring installations stable and attractive in these conditions, you must consider both:

The correct high-temperature adhesive, and
The correct method of application (wet-set vs pressure-sensitive) for the site conditions.

This blog explains:

What high solar gain means for flooring
Why pressure-sensitive installations can be risky in rapidly fluctuating temperatures
How to use UZIN KE 49 HT, UZIN KE 66 HT and UZIN KE 68 correctly
Why conservatories with glass roofs demand special attention
Best practice for installing floors in sun-exposed spaces in line with BS 8203:2017

A bright sunroom with glass walls and a vaulted glass ceiling, featuring a white sectional sofa with patterned cushions, a round wicker coffee table, potted plants, and views of a green garden outside.

What is High Solar Gain and Why Does It Matter for Flooring?

Modern clothing store interior with large floor-to-ceiling windows, neatly arranged shelves of folded clothes, racks with hanging garments, a potted plant, and contemporary black display tables on light wooden flooring.

High solar gain is the heat build-up inside a space caused by sunlight passing through glazing and being absorbed by surfaces. In areas such as:

Conservatories and orangeries (with glass walls or roofs)
South-facing living rooms and garden rooms with large bi-fold doors
Retail shopfronts and display windows
Office atriums and hotel receptions with curtain walling

The floor's surface temperature can rise dramatically. Dark floor coverings can have a much higher solar absorptance factor, particularly in hot weather, sometimes far above the ambient air temperature.

This thermal stress leads resilient coverings such as LVT, sheet vinyl and rubber to expand when hot and contract when cool. If the adhesive cannot resist this constant movement, you will see:

Edge curling
Gapping
Unbonding in localised hotspots

Typical Problem Areas for Flooring in High Solar Gain

You should treat the following areas as high-risk for thermal movement:

Conservatories and garden rooms, especially with glass or polycarbonate roofs
South-facing rooms with large glazing, skylights or roof lanterns
Retail shopfronts with full-height windows and display areas
Entrances and lobby areas with large glazed façades
Office atriums and circulation spaces adjacent to curtain walling

In all these locations, the combination of intense solar gain, potential underfloor heating and rapid temperature swings demands a robust adhesive.

Choosing the Right High-Temperature Adhesive

UZIN provides a range of high-performance adhesives designed for different environments, from homes with floor-to-ceiling windows to highly demanding areas such as conservatories, sun rooms and glazed commercial spaces. Three key products for high-temperature, high solar gain situations are:

UZIN KE 49 HT – high-temperature or pressure-sensitive adhesive for LVT and vinyl
UZIN KE 66 HT – fibre-reinforced high-temperature adhesive for LVT, vinyl and rubber
UZIN KE 68 – one-component heavy-duty adhesive for extreme temperature fluctuations

But when should each be used?

UZIN KE 49 HT – High-Temperature Adhesive for LVT and Vinyl

UZIN KE 49 HT is a high‑temperature dispersion adhesive that can also be used as a pressure-sensitive adhesive. It is formulated for LVT and vinyl floor coverings in demanding environments.

Performance and Recommended Use

Suitable for LVT tiles or planks and vinyl floor coverings
When applied using a wet or semi‑wet bonding method, UZIN KE 49 HT can be used in areas that may experience ambient temperatures up to approximately 60 °C, or where the subfloor is heated from below.
UZIN KE 49 HT provides a strong, continuous bond that resists the expansion and contraction of the floor covering under normal solar-gain conditions.

Learn more about UZIN KE 49 HT

A room with large windows shows partially installed wood flooring over concrete, with adhesive spread on the floor. Furniture, a rug, and potted plants are visible in the background.

Application Methods: Wet-Set vs Pressure-Sensitive in High Solar Gain Areas

A person’s hands are installing LVT flooring over adhesive on a floor, smoothing it down to ensure proper placement and fit.

Wet-Set Installation in High-Temperature Conditions

With UZIN KE 49 HT, different application methods are used depending on the floor covering and site conditions. In areas that may experience elevated ambient temperatures up to 60 °C a wet-set or semi-wet installation method must be used.

With a wet or semi-wet bonding method:

The floor covering is installed into the wet adhesive film
There is excellent transfer of adhesive to the backing
The cured adhesive forms a strong, continuous bond
The installation is better able to resist the expansion and contraction of the floor covering under thermal stress

Why Pressure-Sensitive is Risky in Areas with Rapid Temperature Fluctuations

If UZIN KE 49 HT is allowed to tack off and become pressure-sensitive in areas with rapid temperature fluctuations, its ability to resist contraction and expansion is significantly reduced.

Key risks when using a pressure-sensitive method in these environments:

There is typically less transfer of adhesive to the backing of the floor covering
The bond may be more susceptible to shear forces caused by heating and cooling cycles
LVT floor coverings, in particular, can move, gap and curl as they expand and contract

For high-solar-gain spaces, wet-set installation should be the default approach.

UZIN KE 49 HT is particularly suitable for:

Rooms with floor-to-ceiling windows or French doors
Retail shopfronts with some solar exposure

UZIN KE 66 HT – Fibre-Reinforced High-Temperature Adhesive for LVT, Vinyl and Rubber

UZIN KE 66 HT is a fibre‑reinforced, high‑temperature adhesive designed for resilient flooring installations.

Performance and Recommended Use

Suitable for LVT, vinyl and rubber floor coverings
Designed for areas with high ambient temperatures up to 70 °C
Fibre reinforcement gives excellent resistance to shear forces and movement, helping keep the floor covering firmly in place.

Application in High Solar Gain Situations

In areas subject to high ambient temperatures, UZIN KE 66 HT can be used as a wet-set adhesive to install vinyl, LVT or rubber floors
Installing into a wet or semi-wet adhesive bed ensures optimum adhesive transfer and bond strength

UZIN KE 66 HT is particularly suitable for:

Rooms with floor-to-ceiling windows and conservatories
Retail shopfronts with high solar exposure
Rubber flooring in warm, sunlit zones

Learn more about UZIN KE 66 HT

A man wearing work gloves and kneepads is installing sheet vinyl flooring, unrolling a large sheet of material onto a prepared surface in a bright, empty room with white walls.

When to Step Up to UZIN KE 68 in Conservatories and Glass-Roof Spaces

A modern living room with large floor-to-ceiling glass windows overlooks a lush green forest. The room has light wood flooring, a white sofa, and a small table with a potted plant.

A south-facing conservatory or a room with a high proportion of full glazing. These spaces often experience:

Significant temperature fluctuations over the course of the day
Prolonged periods of intense solar gain, especially in south-facing orientations
A combination of high floor surface temperatures and elevated ambient temperatures

In such environments, the heat can intensify both on the surface of the floor covering and in the general ambient air, placing extreme stress on the installation.

Why UZIN KE 68 Heavy-Duty Adhesive in These Conditions

For conservatories with glass or polycarbonate roofs and similar high-risk spaces, UZIN recommends installing floor coverings with UZIN KE 68, a one-component heavy-duty adhesive, because:

It is specifically formulated to withstand extreme temperature fluctuations
It provides a very high bond strength and excellent resistance to movement
It offers additional security where standard high-temperature dispersion adhesives may be pushed beyond their normal working range

This makes UZIN KE 68 an excellent choice for:

Glass-roof or south-facing conservatories
Highly exposed sun rooms and garden rooms
Projects where the client demands the highest possible level of long-term stability

Learn more about UZIN KE 68

How does underfloor heating affect adhesive selection and compliance with BS 8203:2017?

All UZIN adhesives can be used over underfloor heating systems. While UZIN high-temperature adhesives can tolerate extreme temperature variations, the installation must still comply with BS 8203:2017. This standard requires that the floor surface temperature from underfloor heating should not exceed 27 °C.

Even when using a high-performance adhesive such as UZIN KE 68, it is essential to ensure that the heating system design and the overall build-up keep the floor surface temperature within the limits outlined in BS 8203:2017. If you anticipate that parts of the floor may exceed these temperatures for extended periods, it is strongly advisable to consult UZIN Technical Services.

Learn more in our Under Floor Heating Blog

A room under construction with exposed underfloor heating pipes laid out in a patterned grid; white walls and an unfinished staircase are visible in the background.

Best Practice: Installing LVT, Vinyl and Rubber in High Solar Gain Areas

A person press down on a LVT plank onto a flat surface. The persons hands are visible, focusing on the detailed work.

To achieve a durable and stable installation in sun-exposed spaces:

1. Assess Solar Gain and Heating

Identify zones of intense direct sunlight (patio doors, glass roofs, south-facing façades)
Recognise that conservatories with glass roofs are especially challenging

2. Prepare the Subfloor Thoroughly

Ensure the subfloor is dry, smooth, clean and structurally sound
Use appropriate primers and smoothing compounds compatible with UZIN adhesives

3. Acclimatise the Floor Covering

Store LVT, vinyl or rubber in the installation area (or similar conditions) for the recommended period
Avoid direct sunlight on the products during acclimatisation
Ensure a stable, normal working temperature before and during installation

4. Choose the Right Adhesive and Method

For most high solar gain areas with elevated temperatures up to around 60°C, use UZIN KE 49 HT, or up to 70 °C, UZIN KE 66 HT
Install wet or semi-wet, not as a pressure-sensitive adhesive
For glass-roof conservatories and extreme conditions, use UZIN KE 68

5. Apply Adhesive Correctly

Use the trowel notch recommended in the UZIN technical data sheet
Respect open time and working time, especially in warm conditions where drying is faster

6. Roll and Check Bond

Roll the floor with a 68 kg floor pressure roller in multiple directions
Check edges, corners and thresholds for full adhesion

FAQs For Installing Floors in High Solar Gain Areas

1. Should I use a pressure-sensitive adhesive for LVT in a conservatory?

No. In a conservatory, especially with a glass roof, rapid temperature fluctuations and high solar gain can reduce its ability to control contraction and expansion in LVT, increasing the risk of movement and gapping.

2. Which adhesive is best for LVT in a south-facing conservatory?

In more extreme situations, such as a glass-roof conservatory with significant temperature swings, UZIN KE 68 is recommended.

3. Why is my LVT moving or gapping near the patio doors?

This is often due to high solar gain and rapid heating/cooling, combined with either an adhesive not designed for high temperatures or a pressure-sensitive installation where a wet-set method would have been more appropriate. The result is insufficient bond to resist LVT contraction and expansion.

4. Can UZIN adhesives be used over underfloor heating?

Yes, all UZIN adhesives can be used over heated subfloors, but always follow BS 8203:2017 and the floor covering manufacturer’s guidelines for maximum surface temperatures.

5. Can UZIN KE 49 HT be used to install LVT in a conservatory?

UZIN KE 49 HT can only be used in high-temperature environments when floors are installed using the wet-set or semi-wet method and the conditions aren’t too extreme, such as a partially glazed conservatory rather than a fully glazed, glass‑roof structure. It’s suitable where ambient temperatures do not exceed 60 °C and where the conservatory isn’t subject to very rapid or extreme temperature swings. In highly glazed, glass-roof, south-facing conservatories with significant and rapid temperature fluctuations, UZIN KE 49 HT offers less resistance to LVT contraction and expansion. For those more severe environments, we recommend UZIN KE 68, a one-component heavy-duty adhesive formulated for extreme temperature changes. If in doubt, call our UZIN technical team for advice.