The blower door
A calibrated fan depressurizes the house until the leaks announce themselves in cubic feet per minute. The number before is your baseline; the number after is our report card.
The infrared camera
Ten degrees of January between inside and out, and the camera paints the loss as it happens — top plates, chases, rim joists, every skipped bay a bright confession.
The flow hood
Ventilation is measured, not guessed: every grille balanced to the litre, so the fresh air reaches the bedrooms it was promised to and the accounting closes.
What we do
What the readings turn into
The attic, to R-60
Dams at every recessed light and the hatch, baffles keeping the soffits breathing, cellulose blown deep enough that the joists disappear. The cheapest heat a Lakes house ever buys back is the heat its attic was giving away.
Dense-pack walls
Empty cavities filled through one 2-inch hole per bay at 3.5 lb/ft³ — dense enough never to settle — plugged and patched the same day. The hollow knock of a 1960s wall goes quiet in about six hours, and stays quiet.
Rim joists & cellar ceilings
Two-part foam on the box sill, the plate sealed to the stone, R-38 dense pack under floors over cold cellars. The floor that needed slippers was an air leak wearing a sock disguise.
The method
Diagnostic to test-out, in four moves
The same sequence on every house — instruments first, instruments last, cellulose in between. The only variable is which lines your readings say the house needs.
The diagnostic — $175, credited
Blower door and infrared with the house cold behind it. You watch the walls stream color where the heat is leaving, and the images go in your file before we pack up.
The scope meeting
Findings laid out room by room with a price against each. Nothing is sold that the images did not name, and nothing is named that the images did not show.
The work days
Seal, dense-pack, blow, foam — one crew, drop cloths everywhere, holes plugged as the day advances, and the house stays lived-in throughout.
The test-out
The blower door comes back and both CFM50 readings print on the invoice. The job is a number, not a feeling — and the number moves or we come back.
Why we work this way
The instruments answer to you
A scope written from a brochure is a belief. A scope written from your own walls, with a CFM50 percentage on it before you commit a dollar, is a forecast the weather cannot ruin. Old Lakes houses test between 2,800 and 5,200 CFM50 before we touch them — the diagnostic says which end yours is on and what forty-four percent of it looks like on your meter.
The file outlives the job
The scope carries the CFM50 reduction we expect, in writing. If the test-out reading does not beat it, we return and finish the sealing at no charge and re-test until it does. The images and both readings stay in your file for as long as you own the house — and travel with it when you sell.
The Adder Lakes, 2025 — 2026
Recent files
Six houses from last winter’s book, photographed at the test-out with the insulation card still pinned to the hatch. Nothing styled — a house either moved its number or it did not.
Our 1972 lakeside ranch tested 3,800 CFM50 in November and you could watch the curtains move on the reading day. Larkmere sealed it, packed the walls and blew the attic, and the test-out read 1,650. The February oil delivery went from four to two, and the file they left has a photograph of every hole they fixed. I have shown it to three neighbours like a wedding album.
The scope meeting is the whole product. Two instruments, a table, and a price against each finding — and the line they talked me out of cost more than the line they talked me into. The re-test beat the percentage on the paper by four points.
Every outfit that came before had a catalogue. Larkmere had a camera and showed me my own north wall glowing like a runway. Dense-pack and rim foam later, the hallway you could hang meat in is just a hallway.
They balanced the ventilation with a flow hood and left me the sheet — every grille, every litre. Two years on, the house is tight, dry and the windows do not stream. The file has a number for that too.
Does the infrared scan work in summer?
It needs a temperature difference of about fifteen degrees, so in July we run the air conditioning hard or wait for a cool evening — the camera only cares about the gap, not the season. Winter readings are the sharpest, and around the Lakes we get plenty of those.
Is dense-pack wall fill messy?
One 2-inch hole per bay, drilled inside with a dust skirt, plugged and patched flush the same day. The cellulose stays in the wall — that is what 3.5 lb/ft³ means. Drop cloths everywhere, and the van carries its own HEPA vacuum.
Code says R-49. Why do you blow to R-60?
Because the last four inches are a bag count, not a second job, and at R-49 the attic still carries off a quarter of the heat. On small or already-half-full attics we will quote both and let the readings decide.
Can a house be sealed too tight?
Yes, and the instruments check for it. Combustion appliances get a worst-case spillage test after sealing, and if the house needs make-up air it goes in the scope. Tight and ventilated on purpose is the goal; tight by accident is a defect with a calendar.
What is the payback around the Lakes?
At the median — 44% off the CFM50 and roughly a third off the bill — the work pays for itself in three to five heating seasons, and the utility rebates we file usually pull a season off that. Your own number comes off your readings and your fuel bills, not off this page.
Straight answers, on instruments
The five every Lakes house asks by the second phone call. If yours is not here, the studio line runs seven to five, and January readings are the sharpest ones we take.
Diagnostics book within the week, Lakes-wide — the colder the morning, the sharper the file. (555) 071-3846 · lab@larkmerebuildingscience.example
Put the house on the bench
Tell us the town, the decade the house was built, and which room loses January. The diagnostic is $175 with both readings and the infrared set in your file — credited in full against any work you book. lab@larkmerebuildingscience.example