Preparation of the Base

Prior to lying down insulation all debris & high spots must be removed. If they are not removed they can imprint on the thickness of the finished screed.

Insulation

Make sure that insulation is installed on a clean and even bed to prevent the movement and rocking of boards which are to be butt jointed with staggered joints. In cases where the substrate is particularly uneven, a slurry grout may be required.

Slip Sheets

A thin layer of plastic sheeting should then be placed over insulation and turned up on walls in all rooms. Joints need to be taped and upturns fixed at 150mm above screed levels. (It can be trimmed back after screed is poured.)

Perimeter Details

Provide insulation upstands to all perimeters. We recommend the use of rigid board insulation for cold bridging or 5/10mm polyethylene foam expansion strip to the full depth of the screed. Continue the slip sheet up the face of the upstand, secure with tape to form a watertight seal. Ensure that all junctions with walls and corner details are constructed neatly with the polythene installed fully into the angle leaving no air pockets or voids.

Fixing Pipework

Lay heating system as required ensuring that all pipework is mechanically fixed at 300mm centres. Please be aware that because of the density of the screed, heating systems will lift and 'float' if not adequately secured. We suggest the use of a proprietary fixing system for this purpose. All wet systems should be filled with water to increase density and help prevent lifting.

Holes for Builders Work

Ensure that all apertures are adequately sealed. Any formwork required should be treated as an upstand and prepared as above.

Final Check

Any dust or debris must be removed from all floors either swept or vaccumed as dust may effect final finished floors. Upon completion of installation, inspect the whole system for tears / holes / damage etc and make sure that the whole system remains watertight to receive liquid screed.

Floor Screed Installation

During installation of the floor screed and for three days thereafter, the surface of the screed must be protected from severe draughts. If windows have not already been fixed, clear polythene protection should be installed.

Floor Finishes

When cement based products are applied to the finished floor screed such as levelling compounds or adhesives, the screed must be primed with a suitable and compatible product as recommended by the flooring manufacturer.

 

For more information on McGrath Concrete products please visit http://www.mcgrathquarries.ie