Process of how to fill control joints correctly.
Step 1: Clean out the control joints and vacuum. Run a joint saw through the existing control joint to expose a fresh wall of the joint slightly. Example: If your joint is a 1/4 inch thick, you should run a 1/4 joint cleanout blade or a 5/16 blade after running your joint saw through the existing joint vacuum all remaining dust out of control joint.
Step 2: Fill the control joint with a two-pass system. Make sure to do a quick pass and then come back with a slow pass to overfill the control joint. You must overfill with a two-part polyurea in order for the joint to be shaves flush. Do not use backer rod since full depth is needed. Only use backer rod if filling a cold joint.
Step 3: Allow the material to dry for about 30-60 minutes and shave it flush with a razor scraper. If large enough joint, you can scrape with a ride on the scrapper.
Step 4: Clean out your joint pump. Either you have to get it ready for the next day or do a full cleanout if your pump will set more than 72 hours.
Success factors on filling control joints
- Material has to be at least 78F before you shoot the material. If not, your pump may go off ration. The ISO side doubles in thickness every 10F; it drops.
- Allow the material to sit for a minimum of 30 minutes before shaving.
- Have your razor snapper down low when you go to shave the control joints.
- If using hand tubes, make sure you pump 2-3 times into a bucket before pumping into the control joint. The material has to get mixed in the static mixer tube correctly before filling the control joint.
- Make sure your joint pump is cleaned and working properly.
Equipment List Needed:
- Joint Saw
- Joint blade
- HEPA Vacuum
- Hand tubes- (If doing by hand)
- Joint Pump- Better and more cost-effective if doing more than a 300 linear ft of joints.
- Razor Scraper
- Hand Tubes-If doing by hand
- 10-gallon kits if doing with a joint pump
- Static Mixers
- Razor Scrapper with sharp razor blades.