Denver Crawlspace Blog

How to Choose the Best Crawlspace Company in Denver

Published by Denver Crawlspace Pros | Denver, CO

Crawlspace encapsulation is not a commodity service — the quality of the installation, the materials used, the specifications chosen, and the experience of the company doing the work vary enormously across the Denver market. A poorly installed encapsulation system can fail within years, leaving you with a moisture problem that is actually harder to diagnose and correct than the original condition. Choosing the right company from the start matters.

This guide covers the specific factors to evaluate when choosing a crawlspace company in Denver — including questions to ask, credentials to verify, and red flags to watch for. Denver's market has additional considerations beyond what you might find in national guides, because of the altitude-specific requirements that only companies with genuine local experience will understand.

1. Verify Colorado Licensing and Insurance

The first and most basic credential check is Colorado contractor licensing. In Colorado, contractors performing structural repairs, electrical work, and certain crawlspace work need to be appropriately licensed by the Colorado Department of Regulatory Agencies or the relevant municipality. Ask any crawlspace company you consider for their Colorado contractor license number and verify it at the state licensing website.

General liability insurance and workers' compensation coverage are equally important. If a technician is injured working in your crawlspace and the company does not carry workers' comp, you can potentially be held liable as the property owner. Request a Certificate of Insurance and call the insurance company directly to verify that the policy is active and appropriately limits coverage for your project type.

2. Ask About Altitude-Specific Experience

This is the question that separates Denver-experienced crawlspace companies from those that may have started in another market and expanded here. Ask specifically: "What dehumidifier units do you install in Denver crawlspaces, and how do you account for altitude when sizing the unit?"

A company with genuine Denver expertise will immediately discuss altitude-rated units, the performance reduction that standard units experience at 5,280 feet, and the importance of load calculations based on your specific crawlspace square footage and measured humidity levels. A company that says they install standard residential dehumidifiers, or one that gives you a blank look at the altitude question, does not have the Denver-specific expertise this market requires.

3. Verify the Vapor Barrier Specification

Ask every company you get an estimate from: what thickness vapor barrier do you install? A legitimate Denver encapsulation contractor should be specifying a 20-mil reinforced polyethylene vapor barrier — not 6-mil, not 10-mil, not "heavy duty" without a specific mil rating. Ask for the manufacturer and product name of the barrier they use, and look up the ASTM E1745 classification and vapor permeance rating.

The difference between a 6-mil barrier (ASTM E1745 Class C, 0.4 perms) and a 20-mil reinforced barrier (ASTM E1745 Class A, 0.02 perms) is not minor — it is a 20-fold difference in vapor resistance. Companies quoting with 6-mil or 10-mil barriers are providing an inferior product at, in many cases, a similar installation cost. The material difference should be part of any apples-to-apples estimate comparison.

4. Evaluate the Inspection Process

A professional crawlspace company should provide a free, on-site inspection before any estimate is generated. That inspection should include: a technician actually crawling the entire accessible area of your crawlspace (not just looking in from the access hatch), humidity measurement with a calibrated hygrometer, visual inspection of all framing surfaces for mold and moisture damage, documentation of existing vapor barrier condition, count and assessment of foundation vents, and evaluation of any structural concerns.

If a company provides you an estimate by asking only for your crawlspace square footage — by phone, email, or based on a quick look from the access point — that estimate is not reliable. The factors that drive encapsulation project scope (mold presence, insulation condition, vent count, structural issues, access difficulty) cannot be assessed without a full inspection. An estimate without a proper inspection is not binding and will likely change when they actually see the space.

5. Ask What Happens to Your Existing Insulation

The answer to this question reveals a lot about a company's approach. In most Denver ranch homes with pre-1980 construction, existing fiberglass batt insulation between the floor joists needs to be removed before a new encapsulation system is installed. Leaving compromised, moisture-damaged, or mold-affected fiberglass in place and installing a vapor barrier beneath it is cutting a corner that will undermine the long-term performance of the new system.

Ask: will you remove my existing fiberglass insulation, and is that included in the estimate? What will you replace it with? The answer should be that old fiberglass is removed and disposed of, and that new insulation will be installed as rigid foam on the foundation walls and spray foam at the rim joist — not as new fiberglass batts between the floor joists.

6. Understand the Warranty Structure

Warranty terms for crawlspace encapsulation vary widely. Look for two distinct warranties: a material warranty from the manufacturer of the vapor barrier (Stego Industries provides a 25-year warranty on their 20-mil products) and a workmanship warranty from the contractor covering the quality of the installation. Workmanship warranties of less than 5 years suggest low confidence in installation quality; a 10-year workmanship warranty is the professional standard.

Ask specifically what the workmanship warranty covers — seam integrity, wall attachment, vent sealing — and what the process is for a warranty claim. Companies with strong warranties have strong installation standards; those with limited or vague warranties may not stand behind their work.

7. Check for Permit Knowledge

Crawlspace encapsulation — particularly when it involves sealing foundation vents, which changes the ventilation classification of the crawlspace — may require a building permit in Denver and surrounding municipalities. A knowledgeable crawlspace company should be able to advise you on whether your project requires a permit and should be willing and able to pull the necessary permit and schedule inspections. A company that does not mention permits or actively discourages you from getting one may be cutting corners on code compliance.

8. Red Flags to Avoid

• High-pressure same-day close tactics: Legitimate crawlspace companies provide written estimates with time for you to compare. Pressure to sign immediately during the initial inspection is a sales tactic, not a professional practice.
• Vague or verbal-only estimates: Insist on a written estimate that specifies materials (barrier mil rating, manufacturer), scope (vent sealing, insulation, dehumidifier), and warranty terms before signing anything.
• Fear-based language without documentation: Some companies use alarming language about structural failure, health hazards, or foundation compromise to accelerate decision-making. If concerns are legitimate, they should be documented with photographs and specific findings, not just verbal claims.
• No physical inspection: Any estimate provided without a technician crawling your space is not reliable.
• 6-mil barrier in a 20-mil market: In Denver's climate and with Denver's housing stock, 6-mil barriers are inadequate for long-term performance. This is a material quality issue, not just a preference.

9. Local vs. National Companies

Both local and national crawlspace companies operate in the Denver market, and both can do good work. The most important factors are the credentials, materials, warranty, and inspection process outlined above — not whether the company is local or national. That said, local companies in Denver often have more direct experience with the specific altitude, climate, soil, and housing stock conditions of this market than national franchises that deploy the same system specifications used in markets with very different conditions.