Concrete Block Arches Circles

Home

Sticky Menu

Please help support us Tell friends and colleagues about our apps!

Build concrete core filled masonry block arches without a template See also: Masonry Arch Header Cut and Placement Calculator

When the wall is core filled, the membrane (flashing) around the arch line stops the concrete. Remove off-cuts and extra blocks to reveal the arch.

Width
Height	In
Color

Cut all the blocks before construction. The cut blocks (all halves) that form the arch are numbered sequentially, with off-cuts numbered identically. Take the opening to spring height, then using a standard horizontal head support, go across the head, laying each cut in its place, its matching off-cut on top, with a membrane (aluminum flashing is ideal) between the two. Lay the cut, place the flashing on top of the cut line and lay the off-cut to lock membrane in place.
Use overlapping lengths of thick, strong (aluminum) flashing about 3 feet long so the flashing doesn't get in your way.

An arch has 2 identical sets of cuts
(left and right sides). A bulls-eye (circle) has 4.

Scale

You can easily combine this Template-less Arch System with the Circular Wall System to build circular walls with arches.
Neither system requires a string line, so they combine easily.

You can also use the Gable Cutting System to build arches or bulls-eyes in your circular raking wall. If you'd like more detailed info, please Contact Us

Adjust scale of diagrams to measure 100% scale on screen with a ruler.

Scale

Tap to Transfer this page to Phone via

All Inch inputs and dimensions are actual physical finished sizes

Fraction Precision

Lumber

Prec…

Built something using our calculators? Please Send Photos!
and a description for our Examples list.

(diagrams on this page)

How to Print Large Templates over multiple pages.

If you're cutting blocks, concrete, stone or ANYTHING and there's DUST - DON'T TAKE THE RISK
Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks
And if you're cutting wet, wear a mask - there's dust in the spray mist too!

How should we spell it?	Metre Meter
Results

Many of our calculators can be used for multiple purposes.
If you find a use for a particular calculator in a field not directly related to the name or description of the calculator, or have suggestions for new calculators or improvements to existing ones, Please Let us Know!

Next Calculator ? LET US KNOW !

And if you find the site useful, please Tell a Friend!

If you've benefited from this free service please consider supporting
Blue Dragon Children's Foundation

blocklayer.com

Reviews and Examples

App Directory

X Remove This Margin

Built something using this site?
Please Send Photos!
and description.

Calculator

Print Help Help

Compare Diagrams

Share Print this Page

X Remove This Margin

Please help us support
Blue Dragon
Children's Foundation

Reviews and Examples

blocklayer.com

Online Calculators and Printable Full Scale Template Generators for
Construction - DIY - Remodeling - Metalwork - Crafts - Automotive - Mechanical

All calculators on this site are geometric only.
Check relevant local regulations for appropriate sizes, spacings and all engineering requirements.

Terms of Service & Disclaimer | Privacy & Cookie Policy

Copyright © 1979 - 2026 Greg Tarrant - blocklayer.com

Page 1	Page 2

Page 3	Page 4


Calculator	Spirit Level	Bubble Level