Questions and Answers
What is the minimum thickness required for a bonded screed to ensure adequate bonding with the underlying concrete?
Which of the following best describes the properties of pumpable flowing screeds compared to traditional ones?
What is the recommended minimum thickness of screed when integrated with underfloor heating systems?
What distinguishes a semi-bonded screed from other screed types?
Signup and view all the answers
Which material is primarily used in most pumpable flowing screeds?
Signup and view all the answers
What is the typical ratio of cement to sharp sand in a floor screed?
Signup and view all the answers
Which of the following describes an un-bonded screed application?
Signup and view all the answers
Which material can be added to screed for reinforcement?
Signup and view all the answers
What is the primary purpose of applying a floating screed?
Signup and view all the answers
Which statement is true regarding the final finish of a floor screed?
Signup and view all the answers
Study Notes
Ready-Mixed Screeds
- Factory-mixed sand and cement screeds ensure consistency and quality over site-mixed options.
- Pumpable flowing screeds can achieve very level finishes, primarily using anhydrite compounds based on calcium sulphate.
- Quicker application than traditional sand and cement screeds; minimum thickness for application varies from 25mm (bonded) to 35mm (floating finish).
- Suitable for underfloor heating systems with at least 30mm cover to pipes.
Purpose of Screed
- Provides a level substrate for applying floor finishes.
- Large areas can be laid in bays or strips to prevent slumping.
Types of Screed
-
Bonded Screed:
- Applied within 3 hours of placing concrete to bond monolithically, with a minimum thickness of 12mm.
- A retarder may be used to slow drying.
-
Semi-Bonded Screed:
- Requires a minimum thickness of 40mm, layered on set concrete.
- Concrete surface must be hacked, cleaned, and dampened prior to application for improved adhesion.
-
Un-bonded Screed/Floating Floor:
- Laid on sound insulating material, with minimum thickness of 65mm for domestic buildings and 75mm for others.
- Mix ratio of 1:3; reduces shrinkage with lower cement to sand ratio.
Screed Composition
- Typically made from a cement to sharp sand ratio of 1:3 or 1:4.5.
- Can be applied on solid in-situ concrete slabs or precast concrete floor units.
- Available in various proprietary products, with specifications available from manufacturers.
Screed Applications
- May be bonded directly to the base, laid un-bonded over a damp proof membrane, or as a floating finish over rigid insulation.
- Reinforcement can include fine metal mesh, polypropylene fibres, or fine glass mesh.
Floor Finish Types
- Screed - Provides a base for further finishes.
- Concrete - Cost-effective, strong, can crack, used in wide areas.
- Tiles - Durable and versatile.
- Wood - Preferred in cold climates; recyclable and easily dismountable.
Additional Facts
- Concrete floors preferred in hot weather; resistant to insect attacks but prone to cracking.
- Wooden floors have a durability of 5-6 years; commonly used in bedrooms and stairs, but susceptible to termite attack.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores the benefits and characteristics of factory-mixed sand and cement screeds. It highlights their consistency, application methods, and advantages over traditional mixtures, including pumpable options. Learn about the materials used and their differing thickness requirements.
