form screeds and granolithic finishes

1. form screeds and granolithic finishes

2. Learning outcomes • The purpose of damp proof membranes • The recommended area of separate construction flooring that can be laid without an expansion strip? • The thicknessof aMonolithic floor

3. The materials used in granolithic work include granite chippings 6 mm to dust, and Ordinary Portland Cement Granite chippings and cement are mixed by volume in the ratio5 parts to 2

4. Question The purpose of damp proof membranes is to: Answer prevent damp rising through the structure

5. What is the recommended area of separate construction flooring that can be laid without an expansion strip? Answer 14 square metres Expansion strip

6. form screeds and granolithic finishes • Monolithic systems tend to be the most common methods it fits better with the nature of construction and the set and leave approach of concrete. • In this method a screed is applied to a previously laid concrete base within 3 hours of the base being laid • Monolithic thickness is from 20mm Monolithic

7. An unbonded floor is where no bond to the concrete base is possible owing to its condition. Minimum thickness is 75mm. • A number of different forms of floor construction are included in this type, and are often grouped on their own, e.g. laying a screed on a damp-proof sheet membrane.

8. Floating screed • • An Floating screed floor is where no bond to the concrete base is possible owing to its condition. Minimum thickness is 65mm. • • A number of different forms of floor construction are included in this type, and are often grouped on their own, e.g. laying a creed on a damp-proof sheet membrane, and laying a floor on a layer of insulation

9. Preparation of floors • Remove all loose particles and high points on the floor • Brush all the area to remove dust • For certain floor surfaces , a mix of cement slurry and P.V.A can be brushed into the surface • Smooth surface should be scrabbled to form a key

11. Learning outcomes • The use of a storey rod • How to form Granolithic coves • Why riser boards are cut to a splay:

12. Storey Rod Nosing line Spirit level Straight edge resting on nails Nails Riser Tread Floor line

13. Total Going Total rise Fix riser into position Use a long straight edge to line in other boards Total going equal the proposed length of travel Total riser equals the distance travelled from the floor Treads and risers are in the ratio of 2:1 I.e. for every inch you rise you tread,2inch Riser of 6” = tread of 12” Fix bottom riser

14. Fixing riser boards Stringer Riser board Fixing blocks Struts used to wedge stringer into position

15. Laying a granolithic staircase • Set out • Fix riser boards and stringer • Working on alternative steps • Fill in the treads with granate and trowel to a smooth finish • When material has dried remove riser boards and fill in the missing treads • Face up the risers Struts Stringer Struts

17. Coved cement skirting can be formed in cement/sand screeds and granolithic screeds. They are usually formed by running using skirting or coving trowels in conjunction with battens or screed grounds.