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Residential Comfort & Energy Efficiency

How to Insulate a Cape Cod House: From A to Z

Thursday, December 31 2020

Towson - Maryland

If you have a Cape-Cod style home and you are wondering if you can air seal and insulate effectively - the answer is yes, however not without a good plan.

Houses with Cape-Cod style framing stem from being built in the 1940's and 1950's when the cost of heating was dirt cheap and insulation was an afterthought.

Check out how we sealed and insulated this Cape-Cod style home in Maryland.

If you live in this style home, chances are very good that it has not been properly addressed due to the complexities of the way it was built.

Below, you can take a peek at a recent Cape-Cod insulation project and what steps were taken to seal and insulate. This one is located in the friendly residential Southland Hills community of about 200 homes in the heart of Towson, Maryland. The homes in the neighborhood were built in the 1940s.

The Comprehensive Energy Audit

Having a home energy audit done when you live in a Cape Cod style home might be a good idea if you are looking for guidance on how to properly go about creating better comfort and lower energy bills.

The good thing about working with an energy auditor that has experience is that you can gain insights and avoid pitfalls from a person that has seen these areas before and knows what to expect.

Partnering with a pro can help set you on the right path towards measurable results.

Get a comprehensive home energy audit today!

Bonus Room House!

When I pull up to a home as an energy auditor I have my radar on: What style home is it? What is the footprint of the home? What condition is the home in? Is the heating and cooling gas or electric? These are some of the take-off points to begin a great home energy audit.

One thing at this house stood out to me when I arrived.

A window at the top of a wall within the side gable usually means the house has a "bonus room". Another, more well known way to describe the style of home is Cape-Cod style.

If you have a Cape-Cod style house then you know it really means the bonus room is really just an extra dose of difficulty.

The small attic behind the wall at the bottom of the sloped ceiling is usually hard to reach and a source for discomfort and dust due to old/worn insulation, poorly sealed hatches and general basic neglect (nobody's judging ya!).

Panel that leads to attic space behind bonus room wall. The attic area behind the bonus room wall.

I find these attics in older homes throughout Baltimore County and Maryland for that matter and if you take a drive through this Southland Hills neighborhood, it is easy to see that many of the 200 homes built in the development are all of similar Cape-Cod style.

How to Make Insulation Decisions in a Cape-Cod

The complexities that arise when thinking about how to properly insulate a Cape-Cod style home start to go away the more you see this type of construction style. The problem for most homeowners is that they are not traveling from home to home to manage insulation jobs, taking the time to figure all of this out.

Furthermore, if you are not careful, while expending brain power on thinking through how to insulate the roof or walls or floor, other important things can easily get missed.

For example, HVAC ducts are typically living in Cape-Cod style knee wall attic. It makes perfect sense. It is an easy conduit to run duct work to the different areas of the home adjacent to the attic as well as below.

But, this can also bring a whole new set of issues if the ducts are not maintained or if they are old and have been subjected to other changes the house has undergone through the years.

Take a look at this discovery during a Cape-Cod spray foam insulation project.

Finding a Good Air Sealing & Insulation Treatment Approach

The best approach to take in a house that is a Cape-Cod configuration is to see what the house has to offer as a starting point. What I mean by that is to figure out what areas of the space can be easily accessed.

Collar Attic Plan

Treatment to the top flat portion of the attic (called the collar attic) should be evaluated for treatment including sealing and adding insulation. If space permits air sealing and insulation should be installed.

Look at these similarly constructed homes with varying amounts of space above the top flat ceiling. The lines indicate the approximate ceiling location.

Example Home with only 20" of space Home Where Audit was Conducted has 36" of space to work

In the two different configurations, literally the difference between 16" makes the difference between being able to work in the space or not.

The good news for this home in the Southland Hills neighborhood is that it had sufficient space for a human to work.

Check out some of the details...

The ceiling measures 7' across. A hatch that was cut for HVAC in the collar attic.

A pop up inside the space reveals not much room to move, but a good opportunity
to make improvements, nonetheless.

At the end of the day a air sealing and adding insulation to the collar attic was feasible and recommended to the homeowner. Each Cape-Cod collar attic should be independently evaluated for feasibility.

Sloped Attic Approach

Sloped ceiling portions of a Cape-Cod attic should be evaluated both visually and with thermal imaging. One possible deterrent for homeowners to treat a Cape-Cod attic is that finished sloped ceilings can be costly to re-insulate.

But don't over-think or try to over-do the job. With a few subtle installation techniques, the R-value in the sloped cavity can be increased in some cases and treating areas that are more practical to reach will only improve overall leakage of the ceiling bays.

The solution for this home was to seal the cavity bays from below and from above and leave the existing insulation to keep the project within a budget.

Knee Wall Areas

Another challenge to getting measurable results when air sealing a Cape-Cod style home is getting to all of the small spaces between the roof and the knee wall.

In many cases access will need to be made in several locations, so knowing this and prioritizing improvements is critically important.

As an example, don't re-paint the upstairs bonus room if you are considering insulation or if you are finding this article because you are not comfortable in the space and want to find solutions.

Energy auditing, home performance and the BPI guidelines all work towards finding areas around preexisting homes to treat where the return on investment is positive over time.

In some instances, costs will outweigh value, but when it comes to treating these inaccessible spaces that have older insulation - the gains in energy savings and comfort can really pay off if a little finishing work is required after the project is done adds a little to the overall cost.

Every situation should be evaluated on a case by case basis and a home energy audit is precisely a way to figure all of this out.

Notice how the front dormer windows create multiple areas that need to be treated, making it a bit more difficult.

Check out how we create access to an attic area that is not currently accessible.

Final Plan: Sealing and Insulating in the Best Locations for this House

The stack effect drives the air change conveyor belt inside your home quite a bit in the heating season. This is due to leakage in the basement and in the attic.

During an energy audit I am literally "on the hunt" for places that air can infiltrate (come into your conditioned space) and exfiltrate (your conditioned air goes out). Sealing up these two places in cost effective ways is the name of the game!

So, after careful review and consultation between myself and the homeowner, we decided on the following work scope:

~WORK SCOPE~

Foundation -- Air Sealing / Insulation

Air seal any penetrations at the accessible rim joist in the basement with two-part spray foam (~60 linear ft) which will also insulate the area to R-19.

Attic -- Air Sealing / Insulation

Cut access in three wall locations to gain access to upper floor attic. Reinstall the drywall with removable panel for future access if needed.

Treat three existing attic access areas by adding insulation to each and weatherstripping. (2 wall, 1 ceiling)

Add 5-7” of open cell spray foam to the accessible sloped roof surfaces of the kneewall attic areas (~392 sq ft).

Blow 10” of loose fill cellulose to the flat collar attic using the existing ceiling hatch in the closet (~154 sq ft).

Basement Rim & Band Joist - Every Home Should Get this Treatment by the Way

If you are not sure what the rim and band joist are in your basement and if it is accessible for treatment - you are about to find out!

First, put yourself in the unfinished part of your basement. Usually it is a utility room with HVAC, water heater and maybe washer/dryer.

Identify your foundation wall at the top and you have found your rim and band joist.

Take a look at how the electrical "main" is coming through the rim joist in the basement of this Towson, Maryland home performance home. This is happening in a lot of homes.

Look at the size of that hole. And this is the point - it is a hole going directly to the outside which means this:

Summer: humidity infiltration
Winter: cold air infiltration

Just look at those spider webs. The spiders like to make their traps where air is moving. It is instinctual. So if you see a spider web, air is flowing.

Now get your full frame of reference by watching this short video clip that shows where the electrical main and gas line enter into the rim joist from the outside which appears "invisible", but it is not.

Results - A Look at the Final Project and the Test-Out Numbers

Rim and Band Joist Treatment - Closed Cell Spray Foam

Watch the spray foam team treat a portion of the rim and band joist in this up close and personal clip.

Knee Wall Attic Treatment Before / After

Example of Knee Wall Encapsulation

Blower Door Results

Many factors drive the overall reduction in leakage that each home is schedule to achieve during a home performance project through the BGE program. I make this very clear to my customers that for every house I am believe we can get 30% reduction and don't there is a home that I am convinced we can only achieve the minimum required to meet the program standards (10%) - only to exceed that by a lot.

As a result of many audits and challenging situations when I was wrong, the partnership I formed with this customer went a long way. We both agreed that 20% reduction was a good target and that due to other factors that were not reported here, we will do everything we can to nail the work scope and see where it takes us.

Ultimately, this home performance project achieved an 11% reduction in leakage.

Initial Blower Door Test In CFM: 3775 Cubic Feet Per Minute at Negative Pressure -50 Pascals

Final Test Out Number: 3255 Cubic Feet Per Minute at negative pressure -50 Pascals

Need Advice on How to Do Something Like This?

If you are interested in making your home more comfortable and more efficient, give me a call. We can discuss your situation and likely getting a BGE or Pepco Energy Audit is the way to go.

Incentives through the program can be quite advantageous, particularly for those that know that they have to get this problem resolved once and for all.

Furthermore, an energy audit can uncover other factors that can contribute to your specific issue as each home is different - even the same model across the street.

Give me a call! I'd love to help you out!

Written by Eric Gans
I have over 1000 energy audits under my belt in Maryland. I like to take my personal experiences with each of my audit customers and try to get the things that concern them out into the world so others can make good home improvement decisions - in the right order - according to their needs.

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5 Reasons Your (New or Old) Windows Are Drafty

Tuesday, December 22 2020

Energy auditor and window specials

Written by Eric Gans

I used to be a window contractor. More recently, I have tested thousands of windows as a certified energy auditor.
-2-6 min. estimated read time to get the information you need

Table of Contents

Intro: What Makes Me the Expert?

#1 Places Most Drafts Originate

#2 Home Drafts & Simple Physics

#3 Biggest Home Draft Sources

#4 Basements & Sealing Drafts

#5 Proper Window Installation

Conclusion: Find Your "Real" Issue

As a former window contractor turned certified home energy auditor I have been on both sides of the coin when it comes to replacement windows.

Early on I was convincing people (with the right intentions and wrong information) to replace windows to solve draft issues.

Now, I am on the other side getting called out for an energy audit to check windows because the new and old windows always seem drafty.

In fact, most people immediately connect comfort problems to windows and doors.

But, it usually turns out to be bigger problems that are lurking and they don't cost nearly as much to fix!

It took me years to figure it all out, but when you stop and think about it all for a moment - it really makes a lot of sense.

Here are five reasons that can help you answer the question:

Why do my windows feel drafty?

-Back to Top-

1. The Windows Are Not the Draft Source to Begin With

A draft from a window may not be from a window
Listen to how I had to think about windows in order to look in other places.

FACT: Windows Account for Only 10% of Total Air Leakage in a Typical Home

A misconception for most homeowners is that windows are the only location in your home's "shell" that air can get in and out.

But, there are many other places around your house that might be much more connected to the outside than windows.

And, a lot of these gateways are hiding in plain sight!

If your home is stubbornly drafty you need to think about the issue in three-dimensional ways. This does not mean that you wasted money on windows or that you need special glasses. It just means that you need to shift your hunt for the drafts by starting to look up and down instead of only through the sides.

FACT: Air needs some help to get through cracks and crevices around your home and the pressure inside your home is greatest at the top (attic) and at the bottom (basement/ crawlspace).

"If your home is stubbornly drafty you need to think about the issue in three-dimensional ways...shift your hunt for the drafts by starting to look up and down instead of through the sides."

Read on to learn about the stack effect and how getting the basics from this physics phenomenon can help you begin to think in three dimensional ways about drafts.

-Back to Top-

WATCH ON YOUTUBE

2. Understanding Stack Effect & How it Can Solve Your Draft Issue

In the book Rich Dad Poor Dad by Robert T. Kiyosaki, he talks about how as school children we are never really taught the vital lessons of personal finance and how to stay out of debt and save for the future. A drafty window may not the issue due to stack effect

Similarly, I say everyone should learn about the stack effect when ready to purchase a home.

Understanding how it can play a big part in drafts around the house can really help you with better comfort and overall energy efficiency.

The stack effect can be simply understood by taking one concept we all learn as young children: Hot Air Rises

Here is the part they don't tell you when it comes to your home.

When the warm air rises in your house it creates a lot of pressure at the top and it escapes through all of the holes in your ceiling right up into the attic if modern insulation techniques are not in place.

Many of the holes where this is happening you cannot see, but they do exist!

Check out this 15 second video that demonstrates one common place air escapes at the top floor ceiling.

This problem causes a conveyor belt in a sense. When the warm air goes out at the top new cold air gets drawn in down low - from the leaky parts of the basement or an open crawl space.

As an example, the stack effect is the reason recessed lights in the top ceiling and rim joists down around the foundation should receive way more attention than windows.

Older, slotted recessed lights are no match for the warm air pressure, causing a warm air LEAK! As it leaves, cold air comes in from down low.

As a result - your comfort and money go in the attic and you feel drafts.

An Energy Audit Can Point Out Basement Air Leakage

air leakage top of foundation wall
Shown: Air Leakage in Basement @ Top of Foundation Wall (rim joist) During Blower Door Test

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3. Fireplace Flue & Recessed Lights - Sealing Up "Gateways" to the Outside

One easy way to find drafts is to look for the "gateways" to the outside.

For example, one out of every five customers that I do an energy audit for does not have the flue shut on their fireplace chimney which is a huge gateway to the outside.

Recessed lights are also gateways to the attic (outside) and it is a good practice to check the dampers on any exhaust fans you have venting to the outside. A mis-aligned, damaged or non-existent damper can be a real draft maker.

Sealing Solutions

Covering and sealing can lights at the attic floor
Improving household exhaust terminations
Use a chimney "balloon" to seal faulty flue dampers

Recessed lights are the source of home drafts

Watch How we Seal Big Holes in the Attic

Then We Measure How Much We Sealed the House

Here is Something to Chew On:
Your window contractor will not measure this for you.

-Back to Top-

4. Improperly Treated Crawl Space/ Basement

why windows are drafty

If the construction style of your home is on a crawl space that is open, then you might experience high drafts.

An open crawl space will allow unconditioned air into the the crawl space and unless there is a proper pressure boundary separating the crawl space from the room above, then drafts will surely occur.

Open crawl spaces traditionally have vents in the foundation wall. The theory is to allow fresh air into the space and keep it dry, but in actuality the complete opposite happens in summer. Crawl spaces become breeding grounds for insects, moisture and both want into your house! In winter it is a constant source of cold air into your home.

If you have a full basement it is very likely that the rim joist in any finished or unfinished area has not been properly air sealed and this will allow air infiltration in the basement area that will cause drafts through walls and floors into the living space above.

Check Out this Annapolis House
Learn a Few Ways to Make Your Basement More Efficient

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5. Improperly Installed or Misaligned Windows

Another possibility for drafty new windows, however the least likely, is that the windows were installed improperly or worse yet, not caulked and sealed.

Even if this is the case, it would still be difficult to make a draft problem worse with new windows even if the windows are incorrectly installed due to pressure dynamics in a house.

It is important to note however, that basement windows and windows on the second floor could be susceptible to leakage if not properly installed and sealed due to higher pressure.

Make sure your windows are fully closed and locked!
Another common issue that homeowners with new replacement windows have problems with is making sure that top sash in double hung windows (most common type) are pushed all the way up in the u-shaped header.

When new window users are not accustomed to both sashes of the windows being operable, the thought that the upper sash dropping down does not come to mind and the notion that the windows are leaky is the typical conclusion. Operable windows have several parts that all work together for peak performance. If one thing is slightly off track, the rest of the system can suffer.

Watch: Window Installation Steps