How much does it cost to remove and replace wet or mould-damaged fibreglass batt insulation in a 1,200 sq ft crawl space in Rothesay NB?

Removing and replacing wet or mould-damaged fibreglass batt insulation in a 1,200 sq ft crawl space in Rothesay will typically cost $4,500 to $12,000 total, depending on the severity of the mould, the condition of the crawl space, and whether you encapsulate the space properly after the work is done.

That's a wide range, so let me break down what drives the cost and what you should actually expect for a project like this in the Kennebecasis Valley.

Removal and Disposal

Removing wet fibreglass batts from a crawl space is unpleasant, labour-intensive work. Crews are working in a confined space, often on their hands and knees, bagging and hauling out saturated insulation that can weigh three to four times its dry weight. For a 1,200 sq ft crawl space, expect $1,200 to $2,500 for removal and disposal alone. If the mould is extensive — meaning visible growth on the joists, subfloor, or rim joists, not just on the insulation itself — you may need a licensed mould remediation contractor involved before any new insulation goes in, which adds $1,500 to $5,000 or more depending on scope.

One critical point: do not let anyone install new insulation over or adjacent to active mould growth. The mould must be treated, the wood dried to below 19% moisture content, and the source of the moisture identified and fixed before a single piece of new insulation goes in. Skipping this step guarantees the problem returns, hidden behind fresh insulation.

Finding and Fixing the Moisture Source First

This is non-negotiable. Wet insulation in a Rothesay crawl space is a symptom, not the problem. The moisture source could be ground moisture vapour rising through bare soil, bulk water intrusion from the foundation walls or footing drains, condensation from warm humid air entering through crawl space vents, or a combination of all three. Rothesay's proximity to the Kennebecasis River and its clay-heavy soils mean ground moisture is a persistent issue in this area.

Before any contractor quotes you on new insulation, they should be able to tell you where the moisture came from. If they can't, or if they're willing to just swap the batts without addressing the source, walk away.

Replacement Insulation Options and Costs

Fibreglass batts are the wrong choice for a crawl space replacement. Fibreglass absorbs and holds moisture, loses most of its R-value when wet, and provides no air sealing. If wet batts are what you're removing, replacing them with the same product is a short-term fix that will likely fail again.

The better options for a Rothesay crawl space are:

Closed-cell spray foam on the crawl space walls and rim joists (encapsulated crawl space approach) is the gold standard. Two inches of closed-cell foam on the foundation walls provides approximately R-12 to R-14, acts as both an air barrier and vapour barrier, and completely eliminates the conditions that caused your batt failure. For a 1,200 sq ft footprint with typical 4-foot crawl space walls, expect $3,000 to $6,000 for the spray foam, plus a 6-mil polyethylene vapour barrier on the ground ($300 to $600 installed). The crawl space vents are sealed, and the space is conditioned — this is the modern best practice for NB's climate.

XPS rigid foam on the walls plus ground vapour barrier is a less expensive alternative at $2,000 to $4,500 installed, providing R-10 to R-20 depending on thickness. Requires careful detailing at the sill plate and rim joist to achieve continuous coverage.

Full crawl space encapsulation (spray foam walls, ground vapour barrier, sealed vents, dehumidifier) runs $4,000 to $9,000 for a 1,200 sq ft space in the Rothesay area. This is the complete solution that eliminates the moisture problem permanently rather than managing it.

Rebate Eligibility

A properly executed crawl space encapsulation qualifies for NB Power's Total Home Energy Savings Program (up to $5,000 in rebates) and the Canada Greener Homes Grant (up to $5,000). You must have a pre-retrofit EnerGuide evaluation completed by a certified energy advisor before work begins — retrofits done without the pre-evaluation are not eligible. Given the cost of this project, booking that evaluation first is worth doing.

Hiring the Right Contractor

For a project involving mould, get a mould assessment done separately from the insulation quote — ideally by an independent inspector rather than the contractor who will do the remediation. For the insulation replacement, hire a contractor experienced specifically with crawl space encapsulation, not just general insulation work. Ask for references from similar crawl space projects, verify they carry general liability insurance and WorkSafeNB coverage, and get at least three quotes.

New Brunswick Insulation can match you with local contractors experienced in crawl space work through the New Brunswick Construction Network — find insulation professionals in your area at newbrunswickconstructionnetwork.com/directory?category=insulation.