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Isoboard Ceilings are undoubtedly the most advanced ceiling option on the market. With a smooth, clean white suede finish, there is no need to paint this ceiling. Most people love the Isoboard Thermal Ceilings because water leaks do not easily damage the ceiling. Summit XPS ceilings do not absorb water if a roof leak or water pipe damage in the roof space.

There are two essential facts about XPS ceilings you must know. Firstly XPS will outlast the life of most new homes. Secondly, they are the only actual thermal ceiling on the market. For this reason, the high-density XPS Ceilings is the first choice with most new homeowners.

What Is A Summit XPS Ceiling or Isoboard Ceiling?

Summit XPS ceilings are identical to Isoboard Ceilings as they are both XPS.

Unlike Rhinoboard, the Isoboard thermal ceiling is not affected by water leaks because they absorb less than 0.5% water by volume. As we all know, a roof leak in the home is inevitable at some point. The XPS ceilings are therefore perfect for these applications.

Also, all Isoboard thermal ceilings have an R-value. The R-value of insulation is the ability of the thermal insulation to reduce heat flow into the home. A higher R-value means better thermal performance. Considering that XPS ceilings are available from 30 to 50mm thick is advantageous when creating a thermally stable home.

Extruded Polystyrene is a high-density smooth ceiling board that will outlast the lifespan of most homes.


Bulkhead Ceiling with Rhinoboard
Bulkhead Ceiling Option

Isoboard Ceiling & Summit XPS Benefits

  1. Isoboard is aesthetically pleasing
  2. Stunning tongue and groove finish
  3. It does not require painting
  4. Improves indoor temperature
  5. Saves on energy
  6. The ceilings will outlast the lifespan of most homes
  7. Xps does not absorb water and is not affected by roof leaks.
  8. Installing Isoboard is a clean, almost dust-free application.

The only disadvantage with XPS is that noise travels through the boards as if they do not exist. However, this is not a significant factor. We will have to install additional Thermal Insulation to achieve the required R-value. For these applications, we install class A/A 1/1 non-combustible home insulation like Aerolite Insulation. The reason being is Think Pink is one of the best soundproofing and thermal insulation for roofs. Aerolite has been the soundproofing insulation of choice in Night Clubs and pubs for years.

Installing Isoboard Ceilings

Our ceiling installers have many years of experience installing all types of ceilings. When installing any Ceiling, it is essential to use the services of a qualified ceiling contractor. Firstly, an incorrectly installed Ceiling will shorten the lifespan of your Ceiling and be costly. Secondly, unqualified contractors have no insurance in the event of a subpar installation. They are resulting in the homeowner covering the cost of a ruined ceiling job.

Installing Isoboard Ceilings is different from standard ceiling applications as the Isoboard Ceilings require specific glue and metal clips to ensure a perfect installation. Once installed, Isoboard does not need any maintenance.

What Is The Difference Between Isoboard and Traditional Ceilings?

Firstly Isoboard is a rigid XPS Thermal Ceilings available in 25/30/40/50mm. Because these ceilings are thermal, they also improve the indoor temperature in the house. Secondly, Isoboard XPS does not absorb water. Importantly the installation is clean and dust-free and does not require skimming or painting.

Unlike XPS, traditional ceilings are 6mm thick and require skimming of all the joints. Also, the old conventional Ceilings are affected by water leaks in the roof space and broken pipes. In most cases, we must replace these ceilings every 20 years.

Unfortunately, XPS ceilings do not have a good NRC. What this means is the ceiling boards allow noise to travel through easily. The simple fix is adding Think Pink Aerolite as insulation above the ceiling. Installing Aerolite Insulation stops noise pollution and increases the thermal insulation R-value. We must add good quality Roof Insulation above the Isoboard to achieve the correct R-value required by SANS legislation.


Isoboard & Summit XPS Ceilings

Cornice Fitted To Ceiling Boards
Dropped Ceiling

Underfloor Ceiling Boards

Isoboard Xps Boards for Floor Insulation

Ceiling Boards Between Walls

Isoboard Wall Insulation

Isoboard & Summit XPS Ceiling Specifications

Density  – 35-37Kg3

Compressive strength – 310-360kpa

Water vapour permeability – 369g/m2

Coefficient of Linear Thermal Expansion – 0.49mm per degree C

Dimension Security – <1.0%

Thermal Conductivity – 0.28 W/mk

Recommended Thermal Conductivity Design Value – 0.030 W/mk

Combustibility – B/B 1/2/H&V

R-value of Summit XPS

30mm – 1.00 m2.k/w

40mm – 1.33 m2.k/w

50mm – 1.67 m2.k/w

80mm –  2.67 m2.k/w

R-value Of Summit XPS and Isoboard

We base the R-value of XPS on the 90% aged rate. Because the Polystyrene or XPS r-value deteriorates with age, it is essential to factor the aged r-value when calculating the required r-value for a home. We must also consider the Isoboard Ceilings and the Summit XPS ceilings not to offer sufficient R-value for all regions. For this reason, we must add additional Ceiling Insulation above the ceiling.

The compulsory R-value is 3.70. As we can see below, the XPS R-values are way below the specified value. Significantly because Isoboard is rated B/B 1/2, we as installers insist on installing Class AA 1/1 Non-combustible.


Isoboard Thermal Ceilings Improve Indoor Temperature

Isoboard Ceiling Applications

  1. Installed as a traditional ceiling with the T&G finish
  2. Fitted between beams as a retrofit allowing for exposed beams
  3. Above roof trusses application
  4. We install in factory spaces as well as between suspended ceiling grids as a retrofit.
  5. Placed between bricks in the cavity space for the added thermal benefit
  6. Underfloor applications before the concrete slab are especially beneficial for homes with underfloor heating

Thermal Insulation Benefits

Because Isoboard and Summit XPS ceilings are thermal insulating boards, they can reduce heat flow in or out of the home. We know that energy-saving and global warming have had a significant effect on homes and budgets. The truth is insulated homes will recover the cost of thermal insulation in two to three years on energy saving while offering a more comfortable home in summer and winter.

Summit XPS and Isoboard Ceilings Wall Application

Brick and mortar do not have good thermal properties. We substantially reduce heat from the walls when installing Summit XPS or Isoboard Thermal Ceiling panels in the wall cavity space. The cavity reduces heat buildup by installing a 30mm or 40mm ceiling board in the wall.

Underfloor Thermal Board Application

Installing underfloor thermal ceiling boards reduces the cold air entering the home through the floor. Also, in homes with underfloor heating, we find a substantial cost saving in the price of heating.  As we know, the concrete will absorb significant amounts of heat before warming up the pipes. For this reason, having at least 40mm or 50mm Isoboard or XPS will improve the heating in the home, saving energy.