Crack mitigation in structural fibre reinforced in-situ concrete toppings to beam and block suspended ground floors

This article draws attention to crack mitigation in structural fibre reinforced in-situ concrete toppings to beam and block suspended ground floors.

It should be read in conjunction with previous articles ‘Suspended beam and block concrete floors – guidance on selection of products and materials’ TE15, October 2014 and ‘Structural reinforced in-situ concrete toppings for use with beam and block suspended ground floors in residential construction’ TE20, April 2016. Further reference should also be made to the MPA British Precast Flooring Federation ‘Application Guide for the Specification and Installation of Concrete Toppings to Beam & EPS Block Suspended Floors’, September 2017.

You need to...

• be aware structural fibres have different properties and structural characteristics and are applied at different dosage rates in accordance with independent technical approval body assessments accepted by NHBC 
• recognise these assessments do not remove the need for consideration still to be made of performance of the concrete topping, the design of which should still be undertaken by a suitably competent Chartered Engineer 
• follow published industry guidance and guidance provided on assessments, as well as liaise with fibre and concrete producers and suppliers and Chartered Engineers to ensure details or construction proposals mitigate the risk of cracks occurring due to plastic or drying shrinkage that could be of structural significance and warrant remedial work.