What is the difference between rigid polystyrene and expanded polystyrene

This gas expands when we heat the material. In order to heat the material, we use steam. This heating process forms closed cells of EPS. After the expansion, these beads increase their volume by 40 times than the original volume of the bead. Therefore, it is one of the lightest packaging material.

This makes the transport costs minimum. The most favourable properties of this polymer material include excellent thermal insulation, damping properties and extreme lightweight. These properties make it useful as building materials, packaging material, model planes, etc. However, there are some drawbacks as well. For example, it is not resistant to organic solvents, it is flammable if oil painted, health concerns when using as a packaging material for food items, etc. Extruded polystyrene or XPS is a foam material that we produce from solid polystyrene crystals.

Therefore, in the production process, we need special additives and blowing agents along with polystyrene crystals. We feed these components into an extruder. There, the mixture combines perfectly and melts under controlled conditions such as high temperatures pressures.

This results in a viscous plastic fluid, which is hot and thick. The liquid formed is then continuously extruded through a die and expands during the cooling process. Raissa Trinca Teacher. Is XPS open or closed cell? The closed cell structure of extruded polystyrene XPS prevents water penetration to the structure of the insulation board and provides long term strength and durability.

This process produces a closed cell structure, not a closed cell insulation board, due to voids that can occur between the beads. Taneka Kinsella Teacher. Do you need a vapor barrier with rigid foam insulation?

Rigid foam insulation is usually a qualified vapor barrier. However, an installation between the studs can pose a challenge. To complete the vapor barrier you would want to foam -seal or tape all the sides where the rigid meets timber, because these gaps will facilitate vapor flow.

Segismunda Meissner Teacher. Is XPS a vapor barrier? XPS is manufactured in both an unfaced form or with different plastic facings. However, either way XPS is considered a vapor retarder, not a vapor barrier. Ammara Mccallum Teacher. Why is polystyrene used for insulation? Foamed polystyrene contains millions of tiny air bubbles trapped in the foam, many smaller than can be seen by the naked eye. Air is a poor heat conductor and since polystyrene has a high thermal resistance itself, it's very effective at preventing heat transfer.

Assumpcio Worrings Reviewer. Is foam board a good insulator? Foam board insulation provides good thermal resistance and reduce heat conduction through structural elements, such as wood and steel studs, according to the U. Stelu Arzubia Reviewer.

What is the best rigid insulation? Expanded polystyrene EPS , or beadboard, serves as the best insulating rigid foam for homeowners on a budget.

This material costs less than other rigid foam boards, but still offers an R--value of 3. Hilarion Lebin Reviewer.

What type of foam is waterproof? Open cell foam is not waterproof or water-resistant. In contrast, closed cell foam is water-resistant. However, only high-density closed cell foams are waterproof. Livius Jerusalimsky Reviewer. Is insulation still good if it gets wet? EPS foam is the correct term for any form of expanded polystyrene. Expanded Polystyrene insulation is a lightweight, rigid, closed cell insulation. EPS is available in several compressive strengths to withstand load and back-fill forces.