Technical document

Guide to select and use concrete spacers

Concrete spacers (Concrete rebar support) are a construction accessories material help maintain material integrity and uniformity of the concrete, and provide a cover over the reinforcement that protects against corrosion.

Standard of using Ngoc Lam Sai Gon concrete spacers as below:

Single Cover Concrete Spacers

Single Cover Concrete Spacers are manufactured for 1 size with high strength, and are as strong as the surrounding concrete. They have a wide base for maximum stability when used as recommended for horizontal applications such as […]

Why we choose to use concrete spacers over those made of plastic, granite stone…?

Plastic spacers

Plastic spacers do not bond well with concrete. When the concrete is poured into the form, a small gap is created between it and the plastic. Plastic has a coefficient of thermal expansion and contraction 10 to 15 times that of concrete, and when subjected to temperature variations, the plastic continues to expand and contract at that higher coefficient. At high temperatures, plastic can even melt. The result is a separation between the spacers and the poured concrete, […]

Cover blocks

Cover blocks overview

What are cover blocks?

Cover blocks are used to maintain a specified
distance between the TMT rebar and the
shuttering. (Cover blocks for slab)




Why we must use cover blocks?

– When doing RCC work it is important to
embed the steel in the concrete (also known
as cover) so that the rebar doesn’t corrode
and to provide fire protection to the rebar.

– If we don’t provide the recommended cover
the rebar will corrode with time and will
ultimately result in premature failure of the
– Thus […]