Type of finishes in concrete

Concrete is the basic material of construction , without concrete construction is incomplete

In this article i am going to tell you type of finishes in concrete work are :-

Classes of Finish

• Formed Surfaces
• Unformed Surfaces

Formed Surfaces

Class F.1

This finish is for surfaces against which back fill or further concrete will be placed.
Form work shall be of sawn boards, sheet metal or any other suitable material which will prevent loss of grout when the concrete is vibrated.
Concrete shall not be poured directly against an excavated soil face except where specifically stated on a drawing.

Class F.2

This finish is for surfaces which will be permanently exposed to view. Form work shall be faced with wrought boards with square edges arranged in uniform pattern. Alternatively plywood or metal panels may be used if they are free from defects likely to detract from the general appearance of the finished surface.
Joints between boards and panels shall be horizontal and vertical unless
otherwise directed.
The finish shall be such as to require no filling of surface pitting, butt fins, surface discoloration and other minor defects shall be remedied by approved methods.

Rendering of defective concrete as a means of making good will not be permitted except that, in case of minor porosity on the surface, approval may be given for the surface to be treated by rubbing down with a cement mortar of the same fine aggregate/cement ratio as the concrete. The treatment shall occur immediately after removing the form work. Both cement and aggregate shall be from the same source as the concrete materials.Concrete containing honeycombing, major air holes or similar defects shall be cut out and replaced as directed.

Note :-

No repair shall be executed without approval

Unformed Surfaces

U1: This is a finish for surfaces of roads, subsequent stages of construction bonded concrete topping or cement mortar bed to receive paving. The concrete shall be uniformly leveled and tamped.

U2: This is a broom finish for reinforced ramps and sidewalks.

U3: This is a floated finish for surfaces of beds and slabs to receive mastic paving,tile paving bedded in mastic, and for exposed surfaces when a hard smooth steel trowelled surface is not required.

When the concrete has hardened sufficiently the U1 finish shall be wood floated to give a uniform surface free from tamping marks

U4: This is a hard smooth steel troweled finish for tops of buried foundations,surfaces of concrete paving, tops of walls, coping and other members exposed to weathering. It also applies to surfaces of bed and slabs to receive this flexible sheet and tile paving bedded in adhesives.

The U4 finish shall be steel troweled by hand or machine to produce a dense, smooth uniform surface free from trowel marks.