Trick for Attaching Sill Plates to Concrete Footings




Introduction: Trick for Attaching Sill Plates to Concrete Footings

About: I am an employee of Autodesk, Inc.

Attaching sill plates to continuous footings on the first try can be a challenge.

Traditionally, contractors will lay the sill plate on top of the anchors and bash it with a hammer to mark the location of the anchor bolts. Typically the board will move between hammer blows, and you never end up with a clean mark on the sill plate. Also, the anchor bolts will be slightly out of level, so only the tallest anchors make a mark.

This trick will help you precisely mark the location of anchor bolts in sill plates.

All you need (on top of the anchor bolts, washers and nuts) is two things:

  • chalk
  • some small sections of pipe (1/2 copper couplings fit perfectly over a standard 5/8" anchor bolt)

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Step 1: Prepare the Tallest Anchors

Ok, so you'll need to balance the sill plate on the tallest anchors to start...

  • Measure them all with a tape measure and pick the two or three tallest ones.
  • Thread on a nut, and then put a square washer
  • Adjust the nut so that the washer makes a nice little platform to balance the sill plate
  • Rub some chalk onto the top of the anchor bolt

Step 2: Prepare the Short Anchors

So, the short anchors will need some special treatment to mark the board...

  • Thread a nut onto the anchor
  • Rub some chalk onto the rim of one of our pipe couplings
  • Put the coupling over the anchor so it rests on the nut with the chalk side facing up
  • The coupling should sit just below the top of the anchor bolt (for now)

Step 3: Align and Mark the Sill Plate

Now, we'll need to mark the underside of the sill plate...

  • Align the sill plate with the footing, balanced on top of the tall anchor platforms.
  • Adjust the nut on the short anchors so that the coupling comes into contact with underside of the sill plate
  • Hold the board in place and gently tap the board above each anchor with a hammer (becareful not to move the sill plate!)
  • With chalk, outline the square washers on the tall anchor bolts (just in case we didn't get a good mark from the tapping.)

You should now have some really nice marks where the anchor bolts need to be!D

Step 4: Drill, Baby, Drill!

Now just drill right on the marks we've made. ..

  • Over-drill the holes slightly. 11/16" bit for 5/8" anchors
  • You can now flip the sill plate over and with a hammer, bash it onto the anchors. (it should go without too much of a fight)
  • Tighten the nuts over the square washers

Your'e Done!

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    6 Discussions


    5 years ago on Introduction

    Don't forget your termite flashing.


    Reply 5 years ago on Introduction

    Just use one. Who knows where termites will be in 10 years. Fun fact: there are 3,700 pounds of termites on this planet for every human today. We think we're the dominant form of life on this planet even though they outweigh us by a significant amount.


    5 years ago on Introduction

    Would you pre drill at least one of the holes for secure reference first?

    The easier technique is to pre drill your sill plate and use it to cast the rods in position. It also helps with levelling.