Roof Replacement, James Hardie Siding Replacement, & Gutter Installation in Longmont, CO – Full Exterior Upgrade

Project Summary

In March 2025, our team completed a full roof and siding replacement on this home in Longmont, CO. We installed GAF Timberline ArmorShield II shingles in Pewter Gray for the new roof. The exterior was refreshed with James Hardie lap siding in Evening Blue alongside Cobblestone trim details. Our crew also added a 5-inch seamless aluminum gutter system to protect the foundation. This comprehensive project took 10 days to finish from start to completion.

The Problem

James reached out to us after noticing that the wood lap siding on his home was falling apart. He was ready to get the exterior updated but spent several months gathering quotes from other companies before deciding to move forward with WestPro for both the roofing and siding work.

The roof showed signs of hail damage, and an inspection revealed that the old sheathing underneath had deteriorated in places. The existing siding was beyond simple repair because rotting wood needed replacement to protect the home’s structure from further moisture intrusion.

Why It Needed Replacing

A spot repair would not have been a lasting fix because the weathered wood siding could not be reliably patched alongside new materials, and replacing only damaged boards would leave surrounding aging sections prone to future failure. Additionally, bringing the roof up to current standards required removing the compromised sheathing and installing fresh underlayment rather than leaving worn components in place.

What We Did

We began the project by removing the old roofing materials and replacing damaged sections of the roof decking with new OSB where needed. Our team then installed ABC Pro Guard 20 Synthetic Underlayment across the roof surface, followed by GAF WeatherWatch Leak Barrier in critical areas to protect against water intrusion. We secured the perimeter with a new drip edge along the eaves and rakes before laying down GAF Timberline ArmorShield II Shingles in Pewter Gray. These shingles are Class 4 impact-resistant, providing strong protection for your home. We completed the roof installation with GAF Pro-Start Starter Strip at the edges and finished the peaks with GAF Seal-A-Ridge AS Ridge Cap Shingles in Pewter Gray.

The exterior work included installing James Hardie 8.25-inch HardiePlank Lap Siding in Evening Blue alongside James Hardie 8.25-inch HardiePlank Lap Siding in Boothbay Blue to refresh the siding appearance. We also added James Hardie Panel Siding in Navajo Beige and James Hardie Panel Siding in Cobblestone for texture and durability. To frame these elements, we installed James Hardie HardieTrim in Cobblestone along with primed trim pieces for painting later. We integrated new step flashing, pipe jack flashing, chimney flashing, wall counterflashing, and roof vents into the system to ensure proper water management. Finally, we installed a 5-inch seamless aluminum gutter system measuring 126 linear feet to complete the project.

Project Details

This home on Frontier Street in Longmont needed a full roof replacement and siding work. The project covered 21.5 roofing squares, roughly 2,153 sq. ft., on a nine-facet sides of the roof with a predominant pitch of 6/12. The exterior scope included 1,912 sq. ft. of siding and trim across 17 window and door openings. Twelve linear feet of gutters were also installed as part of the project. The work was completed in March 2025.

Materials Used

• 5" Seamless Aluminum Gutter System
• ABC Pro Guard 20 Synthetic Underlayment
• GAF Pro-Start Starter Strip
• GAF Seal-A-Ridge AS Ridge Cap Shingles in Pewter Gray
• GAF Timberline ArmorShield II Shingles in Pewter Gray
• GAF WeatherWatch Leak Barrier
• James Hardie 8.25" HardiePlank Lap Siding in Boothbay Blue and Evening Blue
• James Hardie HardieTrim in Cobblestone
• James Hardie HardieTrim Primed
• James Hardie Panel Siding in Cobblestone and Navajo Beige

Price Context

This project was completed at approximately $35 per sq ft installed. This figure represents the complete installed scope for this home, including tear-off, trim, and labor, rather than just the roof material alone, which is why a specific home's all-in rate usually runs above the general material range below. Because no two homes are identical, cost varies from home to home.

This price covers a full tear-off and replacement along with permit and installation labor. Homeowners considering a similar GAF ArmorShield II Shingles project in Colorado should generally expect pricing in the range of $6.75–$8.50/sq ft installed.

Homeowners considering a comparable James Hardie ColorPlus siding replacement in Colorado today should generally expect pricing between $19.00 and $23.00 per sq ft installed for the siding itself, with re-sheathing, soffit, and fascia work priced as additional scope on top of that baseline.

Pricing varies based on factors like roof size, pitch, and local building-code requirements specific to Longmont. Class 4 impact-resistant shingles are often required by code here rather than being a simple upgrade option. Pricing reflects WestPro project data and current Colorado Front Range supplier costs. For an exact price on your home, the best next step is a free, no-obligation inspection.

The Result

Finished in March 2025, this home on Frontier Street now features a unified and updated exterior. The project delivered a durable look with Pewter Gray Armorshield II shingles paired with Evening Blue lap siding and Cobblestone trim for a refreshed curb appeal. Projects like this are common throughout Longmont, where homeowners update aging exteriors to improve durability and style.

Thinking about a similar project for your home? Schedule a free inspection with WestPro to get started.