Crawl Space Insulation in Boerne, TX
Crawl space insulation in Boerne typically runs between $1,800 and $4,500 depending on square footage, access conditions, and whether air sealing is completed first – and it should be, always. When the floor system above an uninsulated or under-insulated crawl space lacks a proper thermal boundary, conditioned air bleeds out through the subfloor, floor temperatures drop in winter, and your HVAC runs longer than it should to compensate. We fix that at the source.
At Envelope Insulation Co., operating as Topside Attic Insulation Boerne, we’ve been working in crawl spaces across Boerne and the surrounding Hill Country since 2016. Every crawl space job starts with a written price before any work begins – Haven Standard Clause 1, no exceptions – and ends with a documented photo record so you can see exactly what was done before we left your property. If you want a straight answer on what your crawl space actually needs, call us at (830) 529-7780 and we’ll schedule a free estimate.
Crawl space insulation is a sub-service of our broader Crawl Space Encapsulation & Vapor Barrier in Boerne work. Some homes need encapsulation and insulation together. Some only need one. We’ll tell you which applies to yours after we’ve looked at it – not before.
The Boerne market sits in IECC Climate Zone 2B, which means the subfloor thermal boundary matters in both directions. Summers push 100 degrees for stretches in June and July, and winter nights in the Balcones Escarpment area regularly drop into the mid-20s. An uninsulated floor system loses heat in both directions seasonally, and the crawl space moisture that moves with that temperature swing creates secondary problems – mold potential on joists, pest attraction, and subfloor deterioration over time. For homes with persistent moisture issues, Crawl Space Encapsulation & Vapor Barrier may be needed alongside insulation. We see this pattern regularly in neighborhoods like Esperanza, The Outlook at Hummingbird Heights, and older homes in Herff Ranch where pier-and-beam construction is more common than slab-on-grade.
Wes Okafor built Envelope Insulation Co. around one operational rule: air sealing is a prerequisite, not an upsell. We don’t blow insulation over an unsealed subfloor assembly the way a lot of contractors do. Every job begins with sealing the rim joists, penetrations, and any bypass paths before insulation goes in. The reason is simple – insulation slows heat transfer, but it doesn’t stop air movement. If you skip the air sealing step, you’ve padded a leaky envelope instead of fixed one. We can document the difference with before-and-after blower-door readings on applicable jobs, so you’re not taking our word for it.
When You Need Crawl Space Insulation
Not every Boerne home needs crawl space insulation immediately, but several conditions make it a near-term priority rather than a someday project.
- Floors that feel cold in winter or warm in summer. If the floor surface above the crawl space changes noticeably with the season, the subfloor assembly lacks an effective thermal boundary. In Boerne’s climate, this is most noticeable in February mornings and during July afternoons when the HVAC is fighting the floor from below.
- HVAC runtimes that seem long for the square footage. An under-insulated crawl space forces your system to compensate for continuous heat loss or gain through the floor. Homeowners in the Boerne area often notice this as utility bills that don’t match the home’s age or size.
- Moisture or musty odors originating from below the floor. Without adequate insulation and a proper vapor barrier, warm humid air from the crawl space contacts cooler subfloor surfaces and condenses. This is the starting condition for mold growth on floor joists – a problem we find frequently in older pier-and-beam homes in the historic Boerne district and on larger acreage properties south of Highway 46.
- Visible fiberglass batts that have fallen, sagged, or are missing sections. Batt insulation installed between floor joists is held up by gravity and friction. Over time – especially in high-humidity environments like Boerne crawl spaces that aren’t fully encapsulated – the kraft facing deteriorates, the batts sag, and gaps open up. Sagged batts provide a fraction of their rated R-value.
- A recent vapor barrier installation with no corresponding insulation upgrade. Encapsulation controls moisture, but it doesn’t insulate the floor assembly. If your crawl space was encapsulated but the subfloor never got insulation, you’ve addressed one problem and left the other in place. These two scopes work together, and a lot of Boerne homeowners find out after the fact that they needed both.
- A home built before 2006 with original crawl space insulation. Boerne grew rapidly through the early 2000s, and homes built during that period were often insulated to minimum code at the time. Those minimums are well below current IECC standards. If the insulation hasn’t been touched since the home was built, it almost certainly isn’t performing at its original rated value today.
Our Crawl Space Insulation Process
We follow a fixed sequence on every crawl space insulation job. The order matters as much as the materials.
- Written scope and price before any work starts. This is Haven Standard Clause 1. You receive a flat, written price and a written scope before anyone enters your crawl space with a tool. There are no verbal estimates that shift when the job begins. If we find something during the work that changes the scope, we stop and give you an updated written price before proceeding. This is how we’ve operated since 2016, and it’s not going to change.
- Pre-work blower-door test (applicable jobs). On jobs where air sealing is part of the scope – which is most of them – we run a blower-door test before touching anything. The blower-door depressurizes the house to a standard 50 Pascals of pressure, and the result is a single number – CFM50 – that quantifies how much air the building envelope was losing. That number becomes the baseline. We test again after sealing so you can see the documented change.
- Crawl space inspection and existing material removal if needed. We photograph the crawl space in its current state – access point, joist bays, vapor barrier condition, any existing insulation, and any visible moisture, mold, or pest activity. If existing insulation is degraded, moldy, or contaminated, it comes out before new material goes in. Installing new insulation over compromised existing material defeats the purpose.
- Air sealing – rim joists, penetrations, and bypasses. This step happens before insulation. We seal the rim joist cavities with Demilec or Icynene spray foam, close plumbing and electrical penetrations through the subfloor, and address any bypass paths where conditioned air can move between the crawl space and the living space. Spray foam at the rim joist also bonds to the sill plate and foundation wall, which handles both the air seal and a portion of the thermal value in that area simultaneously.
- Insulation installation in joist bays. Depending on the crawl space dimensions, access, and the customer’s performance goals, we install either Owens Corning EcoTouch fiberglass batts cut to fit snugly in the joist bays, or blown-in material where joist spacing or access makes batts impractical. In Boerne, we’re typically targeting R-19 as a minimum for the subfloor assembly, with R-30 on jobs where the customer wants to exceed code or the crawl space conditions are particularly problematic. The written scope specifies the R-value and the material before work starts, so there’s no ambiguity.
- Documented photo record and post-work blower-door reading. When the crew leaves, you receive a documented photo record of the completed work – not a verbal summary. On air-sealing jobs, you also get the post-blower-door reading alongside the pre-work number. The 365-Day Done Right Promise is in writing and covers all completed work. If anything we installed isn’t performing as scoped, we come back and make it right.
Crawl Space Insulation Pricing in Boerne
Crawl space insulation in Boerne runs $1,800 to $4,500 for most residential jobs. If you’re also considering a Crawl Space Vapor Barrier, that would be scoped separately. Here’s what moves the number up or down.
| Scope | Typical Price Range |
|---|---|
| Small crawl space, batt insulation only, no air sealing (under 800 sq ft) | $1,800 – $2,400 |
| Mid-size crawl space with rim joist air sealing + batt insulation (800-1,400 sq ft) | $2,400 – $3,200 |
| Larger crawl space with spray foam rim joists, full air sealing, and batt or blown-in insulation (1,400-2,200 sq ft) | $3,200 – $4,500 |
| Insulation removal and replacement (existing degraded material) | Add $400 – $900 depending on volume and contamination |
The factors that most consistently push a Boerne job toward the higher end of a range:
- Access difficulty. Crawl spaces with low clearance – under 24 inches – take more labor time. Some older Boerne homes, particularly in the Hill Country Estates area and on properties along the Cibolo Creek corridor, have access points that require additional time to work safely. That labor cost is real and it shows up in the price.
- Existing insulation that needs to come out. If there’s degraded batt insulation, contaminated material, or active pest evidence, removal is a separate labor scope. We don’t skip that step and install over a problem.
- R-value target. R-19 costs less than R-30 in material. The written scope will name the R-value explicitly so you know exactly what you’re buying.
- Whether air sealing is in scope. Air sealing adds cost and is worth it. A job that includes spray foam rim joists and penetration sealing will cost more than batt installation alone, but it’s the only approach we recommend. Insulation without air sealing is an incomplete fix.
Estimates are free and written. If you’ve already received a written quote from another contractor, we’ll give you a free second opinion – we’ll read it with you and tell you what’s in it, what’s missing, and what questions to ask. Call (830) 529-7780 to schedule.
FAQs – Crawl Space Insulation in Boerne
What R-value does a crawl space floor need in Boerne, TX?
The current IECC requirement for Climate Zone 2 – which covers Boerne – is R-13 minimum for floor insulation, but R-19 is what we install as our standard floor, and we typically recommend R-30 when the crawl space has significant moisture history or when the homeowner wants performance above code. The minimum exists to satisfy a permit; R-30 is what actually changes how the floor feels in February and how long the HVAC runs in July. Your written scope will name the R-value and material before any work starts. Call (830) 529-7780 if you want a straight answer for your specific home’s setup.
Can I install crawl space insulation without encapsulation?
Yes, insulation and encapsulation are separate scopes and you can do either one without the other. That said, installing insulation in a vented or moisture-active crawl space without addressing the moisture first is a common way to end up with moldy batts in two to three years. In Boerne, where summer dewpoints pull significant moisture into crawl spaces, we want to know what the moisture situation looks like before we recommend insulation alone. In many cases the better sequence is encapsulation first, then insulation – our full Crawl Space Encapsulation & Vapor Barrier in Boerne page explains how those two scopes relate. We’ll tell you which applies to your crawl space after we look at it.
How long does crawl space insulation take to install?
Most Boerne crawl space insulation jobs finish in one day. A straightforward batt installation in a crawl space with good access and no removal needed typically takes four to six hours. Jobs that include spray foam air sealing at the rim joist, existing material removal, or limited access conditions can run a full eight-hour day. The written scope we provide before work starts will include an estimated time frame so you know what to plan around.
Does crawl space insulation help with moisture problems?
Insulation reduces the temperature differential between the crawl space air and the subfloor surface, which can reduce condensation on structural wood – but insulation is not a moisture control measure and shouldn’t be treated as one. If there’s active moisture intrusion, standing water seasonally, or visible mold on joists, those conditions need to be addressed before insulation goes in. See How Much Does Crawl Space Encapsulation & Vapor Barrier Cost? (2026 Price Guide) - Boerne, TX if moisture control is part of your project scope. Installing batts over a moisture problem traps the problem and creates a worse one. We photograph the crawl space before we start and we’ll tell you plainly what we see – including if the job needs to be sequenced differently than the customer expected.
Why Boerne Homeowners Work with Envelope Insulation Co.
There’s no shortage of insulation contractors working in Kendall County. The difference worth knowing about is how the job is structured before it starts and documented after it ends.
Since 2016, we’ve completed work on more than 9,000 homes – every one with a written price before work started and a documented photo record when the crew left. The 365-Day Done Right Promise is in writing, which means if something we installed isn’t performing as scoped within the first year, we come back and make it right. Not at a discounted rate. Right.
We source materials from manufacturers like Owens Corning and Demilec – not proprietary products you can’t find elsewhere or price-check. The written scope names the product and the R-value. You know what you bought.
Wes Okafor runs Envelope Insulation Co. as an independently owned and operated business. When you call (830) 529-7780, a live person answers – not a voicemail box, not a callback window measured in business days. The technician who shows up is background-checked and uniformed. You’ll get a text when they’re on the way.
If you’re a Boerne homeowner researching this decision carefully – and the fact that you’ve read this far suggests you are – the next step is a free, written estimate. We’ll look at the crawl space, tell you what we find, and hand you a flat price with a written scope. No work starts until you’ve signed off on it. That’s how it works, on every job, every time. Call (830) 529-7780 or visit our home page to learn more about what Envelope Insulation Co. does across the full building envelope.
Written by Wes Okafor, Owner at Topside Attic Insulation Boerne, serving Boerne.