Update with photos- Mason conflicting advice for keeping pests out from fieldstone foundation
Thank you for all your advice and thoughts. Photos uploaded here. Can't have cats due to kiddo having severe allergy.
We live in a New England 1852 house with a fieldstone foundation and are trying to solve recurring rodent entry issues. Pest control companies have not solved the issue and have recommended we contract with a mason since the lattice over our deck is currently removed. We’ve now gotten four very different professional opinions, and we’re hoping for advice from people familiar with old homes with mice entering through basement.
One mason who inspected the house felt the interior in the basement walls were actually in pretty good condition overall and noted they had at one point had interior insulation (before we owned the house).
Below is a summary of the estimates we’ve received:
Estimate #1 (Foundation company – PolyLEVEL system)
- Remove failing/flaking Drylok-type coating from portions of interior foundation walls
- Spray ~1.5" PolyLEVEL foam insulation over interior wall surfaces
- Cover foam with intumescent thermal barrier coating
- Claimed to reduce moisture somewhat, but not waterproofing
- Requires 24 hours no occupancy during install
- Cost: ~$7,500
Concern: whether spraying foam directly onto old fieldstone is appropriate long-term, especially regarding moisture, trapped water, and future maintenance of stone/mortar and that another mason said the interior former spray looked to be in good shape.
Estimate #2 (Exterior rodent-prevention foundation work)
- Excavate 2–3 ft of dirt in the areas discussed
- Remove corroded pointing in fieldstone foundation
- Install new Type-S mortar pointing
- Apply a coat of stucco
- Install 12” x 3’ sharp edge gravel barrier
- Cellar window repair (replace wood with cinder block)
- 7-year transferable warranty
- Cost: $11,750
- Noted as being specifically for rodent prevention
Estimate #3 (Masonry repointing-focused assessment)
Recommended repointing a good portion of the foundation along one side of the house, specifically:
- Small section in front of the porch
- Section under the porch
- Back corner of the house
- One additional section along the side
- Only ground level- not digging down 2-3 ft nor putting in 12” x 3’ sharp edge gravel barrier
- Cost: $1,500
Company #4 (Declined)
After inspecting the property, they declined the job and stated:
“Based on the existing site conditions and the nature of the rodent intrusion concerns tied to the fieldstone foundation, we do not feel we could confidently offer a solution that aligns with the long-term performance standards and warranty expectations our company requires for this type of work.”
We’re trying to understand:
- What actually works best long-term for rodent exclusion in very old fieldstone foundations
Any thoughts from a mason or pest control perspective on fieldstone foundations would be greatly appreciated.
Thank you!!