The busiest siding contractor in unincorporated Boulder County in the last 12 months on file was Mountain Safe Exteriors, with 14 siding permits; 38 siding contractors pulled 132 siding permits on homes there from May 2023 to April 2026, and 78% of their permits a year or more old reached completion.
19 of them filed one in the last 12 months on file. The middle filed job value was $24,000. Next were Westpro Ltd (13 permits) and Northern Lights Exteriors (7); busy is not the same as careful. Side by side: permits filed, share finished and permits in the last 12 months on file for each firm. Pick what you value and the list re-orders.
Data through April 2026 · updated
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The top 9 of the 19 firms that filed a siding permit in the last 12 months on file, May 2025–Apr 2026, ranked by how many they filed, with each firm's permits in the whole file and the share of its permits a year or more old that were finished. This is volume, not quality: a busy firm is not necessarily a careful one.
| # | Contractor | Last 12 mo | Permits | Finished |
|---|---|---|---|---|
| 1 | Mountain Safe Exteriors | 14 | 32 | 62% |
| 2 | Westpro Ltd | 13 | 15 | — |
| 3 | Northern Lights Exteriors | 7 | 17 | 86% |
| 4 | GS Exterior Experts | 4 | 8 | — |
| 5 | 5280EXTERIORS | 3 | 6 | — |
| 6 | Lifetime Home Remodeling | 3 | 4 | — |
| 7 | Colorado Siding Repair, Inc | 3 | 3 | — |
| 8 | Ideal Siding Boulder | 2 | 2 | — |
| 9 | Scottish Home Improvements | 2 | 2 | — |
The 7 ZIP codes with the most siding permits on homes from May 2023 to April 2026. Each opens permits by trade and the most active firms there.
80302 (40) 80503 (26) 80301 (22) 80304 (10) 80466 (10) 80303 (7) 80504 (4)
Before you move a slider, the list is in a default order built only from the permit record: how much of each firm’s record is this kind of job (weight 30), how often its permits reached completion (25), how many permits it filed in the last 12 months on file (15) and how quickly its permits closed (10). Each measure is ranked against the other 38 firms and pulled toward the middle when a record is short.
The order comes from the Boulder County permit file, not from reviews: 19 of 38 siding contractors filed a permit in the last 12 months on file and 78% of their permits a year or more old were finished. Nobody pays to be listed or to move up, and there are no star ratings or reviews. The sliders and presets change the weights, and the order changes with them. How the records work in Boulder County.
From our cross-city data studies: the same measure, read the same way, for every city we cover.
Siding permits and contractors for other places in Denver and Boulder. Each permit office keeps its own file, so the numbers are not added together.
Denver, COBoulder, COAdams County, COAurora, COCentennial, COThornton, COLongmont, CO
We do not rate contractors. In this page’s default order, which uses only the permit record through Apr 2026, the top 3 are Westpro Ltd (15 permits), GS Exterior Experts (8 permits) and Northern Lights Exteriors (17 permits, 86% finished). By permits filed alone, the most active is Mountain Safe Exteriors with 32.
38 firms are on the list; the busiest filed 14 siding permits in the last 12 months on file and the middle firm filed 1 in the whole file. Line them up on the same public measures: permits filed, share of permits finished and usual filed job value. Pick what matters to you and the list re-orders, for example recent activity if you need someone soon. The order comes from the permit record only, and nobody pays to be listed or to move up.
38 firms filed at least one siding permit on homes in unincorporated Boulder County from May 2023 to April 2026; 19 of them filed one in the last 12 months on file.
We have not matched license records to Boulder County firms, so ask for the license number and check it yourself with Boulder County licensed contractors. How to check a contractor's license in Colorado →
Three you can check against this page: “How many siding permits have you filed in Boulder County?” (the middle firm here filed 1; 19 of 38 filed one in the last 12 months on file); “What value will you put on the permit?” (the usual filed value here is $24,000); “Will you pull the permit in your company’s name, and when is the final inspection?” (78% of older siding permits here were finished). All 10 questions and how to check each →
On this page: 38 firms filed 132 siding permits from May 2023 to April 2026, and each firm’s name opens its own permit record. Every number comes from Boulder County Community Planning & Permitting building permits on homes in unincorporated Boulder County (the County's Accela permit layer, which stopped taking new applications on May 4, 2026, so the data ends with April 2026; the City of Boulder and the other cities issue their own permits), with issue dates and declared job values from the Boulder County Assessor's permit file. To see one permit itself, search the address or permit number with the Boulder County permit office. How the records work in Boulder County →
We do not rate or collect reviews. Instead each of the 38 siding contractors here is shown with its permit record: 132 permits, the share finished and usual filed value. Read reviews on other sites and use this page to check them against the record. Reviews vs permit records →
Every number on this page comes from Boulder County Community Planning & Permitting building permits on homes in unincorporated Boulder County (the County's Accela permit layer, which stopped taking new applications on May 4, 2026, so the data ends with April 2026; the City of Boulder and the other cities issue their own permits), with issue dates and declared job values from the Boulder County Assessor's permit file (the County's public permit feed stopped adding new applications on May 4, 2026): 38 firms filed 132 siding permits on homes in unincorporated Boulder County from May 2023 to April 2026, and 19 of them filed one in the last 12 months on file. The middle firm has 1 permit in the whole file. A short record leaves more uncertainty, and some jobs never require a permit.
The middle recorded permit value is $24,000. That is a filed estimate, not a quote or final bill. See how we compare records.
Most Boulder County siding permits are filed in October (164 against an average month of 100); December is the quietest (46). When each trade is busiest in Boulder County →