How to Seal a Fargo House Before Cold Weather

Why is the order of the work the first thing to get right?

NDSU's advice is to seal the known openings and replace damaged screens before cold weather, and to caulk the gaps under doors and around frames. Done in that order, each step keeps the next one from being undone by an open gap.

A household that starts by replacing a screen while a gap at the frame beside it is still open has done half the job. The insect that can not get through the screen still walks through the gap, and the screen is blamed for a result it was never able to deliver. The openings come first for that reason, because they are the routes the screens and the doors depend on.

The openings are the physical gaps: where a window frame meets the siding, where a pipe or a cable passes through the wall, where a vent has lost its mesh and where the trim has pulled away from the house. A household should walk the whole outside and list every one, before it buys a single tube of caulk.

The screens follow. A torn or missing screen on a sunny window is the easiest entry to see and the easiest to fix, and the advice is to repair or replace it rather than leave it. The gaps under the doors come last, because they are the ones that look least important and cause the most surprise when they are finally closed.

What is the walk around the outside of the house?

Walk the outside in a set order, starting on the sunny side, and list each opening with its position and a note of its size. The list is the plan for the sealing, and it is kept for the next autumn.

Start on the south or west wall, the one the afternoon sun reaches first. Look at each window frame where the trim meets the siding, at the top and the sides, and note any gap, shrinkage or daylight. Look at the threshold of each exterior door and at the sweep. Look at the screens, one by one, for tears and bends.

Move around the house clockwise, and treat each side the same way. Check every vent for its mesh, every pipe and cable for a gap around it, and every place where the siding stops short of the ground. Note the foundation line and any crack, and mark the ones that look like a building matter rather than a pest matter.

Finish the walk at the garage and any outbuilding. A garage door with a gap at the bottom, a frame with daylight and a shed wall that meets the ground with a gap are all common, and they belong on the list alongside the house.

Which material closes which gap?

Caulk closes thin seams that move slightly with the seasons. Expanding foam fills larger voids and must be kept away from the frame. Weatherstripping and sweeps belong on doors that open and close. Mesh replaces torn screens and vent covers.

Caulk is the everyday material, and it is the right choice for the seam where trim meets siding and for small gaps around a window. It is applied as a continuous bead and smoothed, and it is most effective when the surface is dry and clean. Its limit is size: a gap wider than a finger needs more than caulk, and a thick bead of caulk cracks rather than bridging a void.

Expanding foam fills larger voids, such as the gap around a pipe that passes into a wall cavity. It needs care. As it cures it expands and can push against a window frame and warp it, so it is kept back from the frame and cut back when it has set. The surface is then sealed with a finish that matches the siding, and a sealed foam joint is an easier job for the next autumn than an open one.

Weatherstripping and sweeps are for doors. A sweep that is worn through is replaced, and a weatherstrip that has flattened is replaced with one that fits the door. A threshold that does not sit level on the floor is adjusted or replaced, because no sweep works over a threshold that rocks.

Mesh is for the vents and for torn screens. Mesh that is rusted or crushed is replaced, and a vent cover that has lost its louver is listed for replacement, because the mesh alone will not hold it in place.

Where does sealing stop and a repair begin?

Sealing covers small gaps in the envelope of the house. A split siding panel, a window that will not close square, a sill that has rotted or a foundation crack are building repairs, and they belong to a tradesperson rather than a tube of caulk.

A caulk line can hide a building problem, and that is the reason to be careful. A window that does not close square has a sash or a frame problem, and covering the gap with sealant leaves the problem in place while hiding it from view. A split siding panel lets water in, and that is a repair the homeowner should have looked at by a contractor.

A foundation crack that runs through the mortar, or one that is wider at one end, is a structural question rather than a sealing one. The walk notes the crack and its direction, and the list says it needs a building check. Sealing it with foam or caulk alone is not the right response.

The list the walk produces should mark each item as closed, partly closed or open, and say what an open item needs. That makes it easy for a household to take the building items to the right person and to see which of the pest items remain.

What is the sealing timetable for a Fargo autumn?

The timetable below starts with the walk and ends with the check in the first warm spell after the sealing. It follows the NDSU advice on timing, which points to the period before cold weather arrives.

The first step is the walk, done in early autumn while the walls are still warm enough for the bugs to be active. The list is made then, and the materials are bought once the list is known. A household that buys the materials before the walk tends to buy the wrong ones.

The second step is the sealing itself, done in the dry days that follow. The openings are closed in the order of the list, the screens are repaired and the sweeps are fitted. The work is done before the first hard cold, so that the caulk and foam can cure in mild weather.

The third step is the check in the first warm spell after the sealing. The sunny walls are watched, the screens are checked for bugs at the glass and the openings are walked again. A cluster that forms again is a sign that an opening was missed, and its position goes on the list.

How do you check the seal after the work is done?

Check the seal in the first warm spell after the work, on the sunny walls and at the screens, and walk the openings again against the list. A check that finds nothing new is the result the sealing was for; a check that finds a fresh cluster or a new gap sends the list back for a second look.

The first warm spell after a sealing job is the test. The sun returns to the south and west walls, the insects that gathered there are still outside, and a missed opening will show itself as a cluster on the wall next to it. A household that watches that wall for a few afternoons learns more about the house than any single walk can show.

The second part of the check is the screens and the doors. Look for bugs at the glass of the sunny windows and on the sill of each door. A bug on the inside of a screen that was repaired means the screen itself has a gap at the frame, and the repair has to be finished at that point.

The third part is the list. Each item that was closed gets a tick and the date. Each item that was left gets a note of what it needs and who should do it. The list is the record for the next autumn, and it shows the next walk where to begin.