Hardieplank Siding: How to Install Fiber Cement Siding for your New Room Project

Here’s a quick guide of how to install Hardie Plank siding in a new room.

• 1. To begin, cut corner trim boards to length by scoring with a razor knife and snapping.

• 2. Immediately, prime the cut ends of the Hardie boards as instructed by the manufacturer.

• 3. The goal here is to build corners using 1x4 cementation boards before attaching them to the walls.

• 4. You can use a 2x4 piece of lumber as a temporary block to help create the corner.

• 5. Apply construction adhesive to the entire length of the edge of the upright board and then carefully line up the two edges of the boards to create the corner.
• 6. Once in place, carefully add a few screws along the length of the corner to secure it in place.

• 7. Now you have to be careful with screws near the edge of Hardie panel and it's a good practice to pre-drill the holes first.

• 8. Then set the assembled corner in place in the orientation you desire and secure it to the wall using trim head screws.

• 9. You must pre-drilled holes as well and add screws on both sides of the corner.

• 10. Before attaching the inside corner trim piece, apply a generous bead of sealant at the corner seam to prevent water intrusion.
• 11. Then place the trim in position and mount it with several trim head screws.
• 12. Now you are ready to install the first lap board but before you could do that you had to create a bump out.

• 13. To do this, glue pre-primed rip pieces of hardie plank to the underside of the lap board. The rip pieces were roughly an inch and a quarter wide and glue within 2 inches at the bottom of the lap board.

• 14. Position the board in place so it overlapped the new room concrete floor but yet several inches above the old concrete porch pad.

• 15. Check for level and screw it into position placing fasteners about an inch and a quarter from the top of the board.

• 16. Then cut the next piece of plank using a razor, scoring both sides and snapping.

• 17. This board was placed so it overlapped the first board by about 2 inches which was enough to cover the screw heads in the first board.
• 18. Cut the link slightly shorter than the full distance of the wall to leave a small gap between the lap board and the trim board pieces for expansion considerations.

• 19. Continue to cut planks in length making sure to prime every cut end before installing.

• 20. For extra protection, back caulk joints prior to mounting the siding boards.
• 21. Once in place, secure the panels with Hardie backer type screws placing the screws in the proper location about an inch and a quarter below with the top edge.

• 22. Measure up from the installed plank to mark a level line to locate the top edge of the next siding piece.

• 23. Around window openings, carefully cut voids for the planks to properly fit.
• 24. When you reached the top of the wall, place a narrow ripped siding strip to cover screw heads and attached it using trim nails.
• 25. For the next wall, start by installing the remaining corner using trim head screws like before.

• 26. Then install the sliding door window trim overlapping the door frame slightly.

• 27. Make sure it was level and attach it with the trim head screws.
• 28. Then, repeat the process to perform on the first wall.

• 29. Make a bump out on the first section of siding and install it in line with the first board on the first wall, placing screws one and a quarter inch from the top edge of board.

• 30. Continue to add siding panels up the wall in this fashion making sure to prime all cut ends before installation.

• 31. The third wall was the same procedure.
• 32. Start by attaching the wall trim board.
• 33. Then, set the first plank panel with the bump outs attached underneath.

• 34. When you got to the electrical box, you have to cut out spaces in 2 planks.

• 35. The last full plank needed three openings cut into it to accommodate the windows.

• 36. From there it was just a matter of cutting smaller planks to size and installing them the rest of the way up the wall.

• 37. After completing the installation, paint the new siding with a quality primer suitable for cementitious surfaces and then apply a couple of coats of high quality exterior paint.

• 38. This is the completed exterior for a new room edition that was created from an existing patio space.

Special thanks to MrKistel for this wonderful project. Please subscribe to his youtube channel for more awesome how-to project tutorials.