I’m Andy Parkin, Managing Director of the Multi-Award Winning Speed Screed. I’m here to talk about lightweight screed.
A variety of constituents make up lightweight screeds. These can include fine limestone, ordinary cement (Portland preferred), perlite lightweight aggregate, and specially picked foam stabilising agents. To ensure that the quality remains consistent, the lightweight screed is manufactured under controlled conditions. Lightweight screed is popularly used for thermal insulation on the roofs and floors.
Lightweight screeds are mixed with highly insulating premixed mortar to be used for attics, balconies, and both flat and sloping floors. Lightweight screeds play an important role in lessening the weight by up to 80% as compared to regular concrete/screed.
Tarmac lightweight screed is a pretty popular option. It is a pre-blended, dry bagged lightweight screed. When you use lightweight screed on roofs, it is usually covered with mastic asphalt or felt. It is one of the most highly insulating premixed mortars.
Properties of Tarmac Lightweight Screed
If water is run through the screed once it is set, it will not decompose or disintegrate in any way. This lightweight screed is not impacted by cold temperatures whether it is set and dried or it is unused, in powder form. Cement-based products generally shouldn’t be laid in conditions below 5°C.
A few features of Tarmac Lightweight screed are:
Duration of Drying:
This lightweight screed dries quicker than traditional sand and cement, the precise period relies on the screed’s depth, climate conditions, ventilation, and sub base.
Preparation of Floor and Installation:
The substrate should be free from dust and clean from grease, dirt, and any other pollutants that could impact bonding. Ensure that the substrate is wetted completely using clean water. Also, make sure that you brush the primer or the bonding agent into the surface as per the instructions of the technical datasheet.
Application and Thickness:
When laying, first of all, spread the screed over the floor area and then work it into the base. Then, ensure that the screen is evenly and thoroughly compacted. Do not trowel excessively as it could lead to surface dust and crazing. Then, to help the monolithic topping, rake over the surface.
Do trowel too much. Protect the screed from any kind of damage after laying. The screed must be cured appropriately. Also, see that the screeds remain covered for at least 3 days by protective sheeting. Avoid using air blowers and underfloor heating or any other means to accelerate the drying process in its initial stages.
When you use lightweight screed for flooring, it requires topping as well. An ideal specification for your floor would be 1:4 cement screed and ready mixed sand along with a monolithic topping of at least 15mm.
I hope this helps with your “lightweight screed” questions, if you would like any further help please get in touch.