Blinding
Contents |
[edit] What is blinding in construction?
In construction, 'blinding' typically refers to a base layer of weak concrete or sand that is laid above a layer of hardcore to provide a clean, level and dry working surface. A thin layer, usually around 50 mm (2 inches) thick, of blinding is poured over the hardcore, sealing in the underlying material and levelling off the surface.
The concrete used for blinding is weak compared with structural concrete, and can withstand lower loading. If necessary, steel mats can be used to reinforce either the entire blinding layer or the specific areas of high loading.
[edit] What is blinding for?
If a damp-proof membrane (DPM) is to be placed above it, the blinding will help prevent it from becoming damaged by the hardcore.
If a damp-proof membrane is not being laid directly above the blinding layer, it provides a sturdy surface on which a pavement, concrete floor, footing, raft foundation or reinforcement can be positioned, and it prevents the concrete from seeping down into the hardcore. It also reduces the amount of moisture penetrating up into the concrete.
A blinding layer can also provide a more useable working surface on construction sites, it creates a cleaner and more even site and provides a suitable ground for the storage of materials.
[edit] Alternative definitions of blinding
NB Culvert, screen and outfall manual, (CIRIA C786) published by CIRIA in 2019, gives an alternative definition of blinding as: ‘A temporary accumulation of impermeable debris on the lower part of a screen that creates a ‘weir’ effect, reducing the flow area and increasing upstream water levels. Preferred term is variable blockage.’ Where a screen is: ‘An arrangement of bars, grids or poles placed in a watercourse.’
[edit] Related articles on Designing Buildings
Featured articles and news
A transformative shift in the design, construction and management of built assets.
Apprenticeship announcement by the Prime Minister
Welcomed but with call for more actionable detail.
Heat pump announcements, what homeowners need to know
An 'ultimate guide to heat pumps' from a heating company.
Construction contract awards reach 7.1bn in February
Their highest level in seven months.
The journey to sustainability in heritage
Research is the key to better understanding.
Heritage approaches to adaptation, mitigation and loss.
Bridging the gap between policy, finance and installation.
Development on brownfield land
Definition, background, policy and the latest consultation.
With the Design Framework for Building Services.
Retrofit of Buildings, a CIOB Technical Publication
Pertinent technical issues, measures and the roles involved.
ECA joins HSE campaign to support mental health
Working Minds’ five simple steps based on risk assessment.
Mental health in the construction industry
Mental health issues in brief with related articles.
Transitional arrangements, Building Control and the BSR.
For pre-October buildings with substantial progress by April.
Why quality counts in domestic ventilation systems
From products, to systems to the installation.
Empowering the Future with CIOB Academy
Lifelong learning, upscaling, and reskilling for the built environment.
Comments
[edit] To make a comment about this article, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.