Need an Objective Standard for Broom Finish on Exterior Concrete

Specification & Product Discussions Specifications Discussions
1

Looking through ACI material, all I can find are standards for flatness, strength, and such. For finish quality, all I see is a recommendation that a mockup be done and approved before construction.

Broom finish on concrete is not an exact science where absolute perfection is achievable, so when an owner wants to nit-pick the flatwork on their hands and knees after the fact, what objective standards can be referenced?

2

Nick,

Please send me an email to wayne.yancey@arcadis.com.

I have a SECTION 033510 MONOLITHIC CONCRETE FLOOR FINISHING that I have used for the past 30 years. It includes sidewalks and exterior ramps.

And it is free.

Wayne

3

Wayne, I’d be curious about the general approach for a broom finish used in that section. I never had an issue with this on a project, but I totally have had clients with the kind of mind-set that Nick is talking about (insert eye-roll here).

4

We’ve used the terms, “Light Broom Finish” and “Coarse Broom Finish” my entire career with no issues from clients. Still, a subjective term up to interpretation by the GC. I’ve never run across any other reference to use for this. I found this reference from CSI:
https://www.constructionspecifier.com/specifying-broomed-exterior-concrete-surfaces/

5

This absolutely requires a mockup in some corner of the site. ACI defines the following:

  1. fine broomed (less than 1/32 inch, created with horsehair bristle
  2. medium broomed: 1/32 to 3/64 inch, horsehair or synthetic bristle broom
  3. heavy broom: 3/64-1/8 inch depth with stiff-bristle concrete broom.
    ACI 310R-13 “Guide to Decorative Concrete” provides the definitions but that document is very specifically not a specification – it relies on agreement between owner, architect and finisher.