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How to Insulate a Well Pump House

well pump house insulation

How to Insulate a Well Pump House Blog Feature
Mark Israel

By: Mark Israel on January 24th, 2020

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A good portion of the year you might not think too much about the pipes in your pump house, but when the temperatures start to drop and those pipes freeze, it’s a headache you’ll be dealing with all season long.

Your well pump house is providing water to your troughs, barn, and in some cases your home, so you need those pipes working and that pump putting out the water you and your animals need.

Now the freezing pipes are just one reason you will want to insulate your well pump house. There are also instances of controlling moisture in the pump house because too much moisture over time can cause damage to the wiring, as well as rusting to the pipes.

As a project manager here at RetroFoam of Michigan, I have helped many homeowners in the rural areas of the lower peninsula insulate their pump houses with closed cell spray foam. While we only install foam insulation, there are other options available to you like foam board, fiberglass, or the closed cell spray foam we offer.

We want to educate homeowners and really give them all of the information they need to make an informed decision for their project. In this article, I will discuss what the options are to insulate a well pump house, the pros, and cons of each, how they are installed, and which material will be the best insulation.

What are the Best Insulations for a Pump House?

When it comes to insulating a well pump house I briefly mentioned before that the insulation options available are foam board, fiberglass, and closed cell spray foam.

Here is a little bit about each of these insulation materials.

Foam Board Insulation

Foam board insulation is rigid panels made up of either polystyrene, polyisocyanurate, or polyurethane. 

The foam boards can be used to insulate any exposed cavity. The boards are offered in a variety of thicknesses, lengths, and facings. These varieties make it easier to customize the boards to properly fit your project.


  • Rigid foam boards are water-resistant. This limits the amount of moisture that can build up in the structure.
  • Foam board can reduce the chance of mold growth.


  • The joints between the sheets must be taped or caulked to prevent airflow.
  • The foam boards must be cut to fit together perfectly where they are installed, or air will leak around them.
  • Pests can chew through the material.

Fiberglass Insulation

Fiberglass insulation consists of fine glass fibers.

Fiberglass batts can be placed into standard open cavities. It comes in either the form of batts or loose fill, but of the two batts are what is recommended for well pump houses.



  • Fiberglass still allows for air movement through it.
  • If it comes in contact with moisture, the fiberglass can retain it which leads to the growth of mold.
  • Pests will pull and tear at the material using it as bedding.

Closed Cell Spray Foam Insulation

Closed cell spray foam is a spray-applied plastic insulation that forms continuous insulation, as well as an air seal.

Spray foam can be installed into any open cavity. Closed cell spray foam is durable and has a low expansion rate.


  • Closed cell spray foam in moisture impermeable, which means moisture can’t move through it. It also doesn’t retain any moisture it comes into contact with.
  • Spray foam conforms to the space where it is applied.
  • Foam insulation doesn’t serve as a food source or bedding to pests.


  • Closed cell spray foam is more expensive than the other insulation options for the well pump house.
  • While foam board and fiberglass can be installed as a DIY project, the better option for spray foam is to have a professional install it.

How to Insulate a Pump House

Pump houses come in all shapes and sizes, but one thing they all have in common is they are either made from lumber or block.

The process for certain materials varies depending on what the pump house is made of. Below I will explain the process of how to insulate a pump house for each material, as well as how it’s done if the structure is lumber or concrete blocks.

Before we get into installation, something that goes hand in hand with adding insulation to conquer the challenges with moisture and frozen pipes is to insulate the pipes themselves.

This can be done by wrapping the pipes with heat tape, fiberglass, or sprayed with open cell spray foam

How you insulate the pipes comes down to what you prefer for the project.

How to Insulate a Well Pump House with Foam Board

Insulating a well pump house with foam board can be done, but you’ll need to do some measuring.

This is because the foam board has to be cut to fit perfectly where it is going to be installed.

If the pump house is made from lumber, then the foam board can be installed in the framed walls. Caulk and tape need to be used to seal around the seams. If you plan to also insulate the ceiling, then an adhesive will need to be used on the backside of the boards to ensure it stays in place.

If the structure is constructed using concrete blocks, again adhesive will need to be used on the backside of the boards so it stays put. 

One thing you’ll want to keep in mind is rodents and what they will do to the foam board. Usually, in a pump house there isn’t anything covering the foam boards, so rodents will have access to it and might even chew through it.

How to Insulate a Well Pump House with Fiberglass

Fiberglass insulation can only be used in pump houses made from lumber.

This is because the fiberglass batts are stapled into place and there is no way to keep them in place on concrete block walls.

In a wooden pump house, the fiberglass batts are installed in the framed walls and framed ceiling then stapled into place. During the installation, it’s important to not cram the insulation into the cavities because this can lead to gaps which means more air movement into the pump house.

How to Insulate a Well Pump House with Closed Cell Spray Foam

Closed cell spray foam install is similar whether the well pump house is made of wood or concrete block.

If the pump house is made from lumber, then the old insulation needs to be removed before the foam is sprayed. The closed cell is sprayed in those studded out walls and ceiling.

If the well pump house is concrete, then the spray foam is just sprayed directly onto the concrete.

In both installations, an air seal is created which helps prevent those frozen pipes and mold growth. 

Insulating a Well Pump House with Foam

In most cases, I have found that spray foam insulation is the best insulation option for a well pump house.

With each season, closed cell spray foam keeps the pump house a conditioned space, so it doesn’t matter what the weather is doing outside. The air seal created by foam insulation will keep out the air that has led to moisture issues and those dreaded frozen pipes.

The decision is up to you and I hope the information helps you make the best decision for your project.

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About Mark Israel

Mark's experience as a licensed builder and familiarization of the foam insulation product are just some of the knowledge he brings to homeowners. Mark takes care of customers during their estimate experience. He enjoys the knowledge and wisdom he gains from meeting new people every day. During his downtime, Mark likes to do yard work, golf, hunt, fish, and watch sports. He also enjoys spending time with his wife and family.