Chances are that you love your bonus room or are planning to love your new bonus room. You have probably made all types of plans and created storage space, added beautiful windows, maybe you even put in a skylight or wood floors. 

So why is the floor (and the entire room) so dang cold in the winter and hot in the summer? 

If you’ve got a bonus room in the attic or over the garage, you are probably nodding your head in agreement. 

Let’s face it, Chicago winters are tough, and no one wants to spend the winter holidays shivering inside their own home. 

I’m going to explain why this happens, what the common ways are around this issue why these solutions fail, and how you can easily solve this problem with proper planning and SPRAY FOAM INSULATION. 

Why Floors Are Cold 

While building codes may indicate that floors need to be insulated to an R-30 value, it is not at all uncommon to find floors that are at or below freezing when it is at or below zero outside. 

If you’ve ever sat in a bonus room and felt freezing cold air on your feet but the room itself is comfortable, then you know what I’m trying to describe. 

How does this happen?

When it comes to a bonus room, which is typically in the space over the garage, it is nearly impossible to install fiberglass batt insulation that will stay in constant contact with the floor above, to cut correctly to conform with the joist space and that all penetrations are properly caulked/ foamed to stop air leakage.

A few weeks after inspection, it is common that contact to the subfloor of your bonus room is not maintained, it allows spaces to air to circulate below your subfloor which will eventually start the process of condensation and further compression of that fiberglass batt to the ceiling of your garage proving that it is totally useless. Gravity works…. If the batts are not secure they will find their way to the bottom of the cavity within a year or two.

Using spray foam insulation during estimating, planning and construction is not typically an expense that most residential contractors are going to include but I can tell you after 15 years of selling foam, you will not be happy if you don’t!

Rooms Other Than Just Bonus Rooms Are Also Affected 

Most newer homes today are designed to have a unique or open feeling to them. This means that cold floors that are over unconditioned spaces such as porches, crawl spaces, or floors that extend beyond the exterior wall of the building can make for very cold floors.

Many new homes now come with wood floors, which only exacerbate the problem. Floors were certainly as cold as you are experiencing now, in the home you had twenty years ago but the wall to wall carpet upstairs, with a pad below it provided protection for your bare foot on the coldest nights, from feeling the cold.

This is why most builders face a complicated balancing act. They need to keep the cost of the home or bonus room affordable, and so they do a minimum amount of insulation, rarely consulting with a person like me before construction begins. 

Heated Plenums

One compromise is a soffit installed in the garage and insulated with a fiberglass batt material. This allows heated house air to be ducted into the space created under the floor without taking square feet of floor space away from the project. 

While this may help provide heat to the project, it doesn’t really address the long-term solution of comfort. 

Water pipes that are run within the plenum commonly freeze since there is no requirement for the proper insulation of the heated plenum.  Cold like February of 2021 will certainly expose these failures and cost you thousands of dollars in damage because you hired the wrong contractor and trusted them to insulate/ design properly.

When the plenum/ ceiling of your garage is not properly air-sealed, it can allow heated humid air to move through the insulation and create condensation, which can lead to mold and other structural problems. 

While there are workarounds, the cost is usually so high that most builders simply hope for the best. 

This inferior design will end up costing the building owner higher energy bills for as long as the building is standing. 

All of this is really unnecessary when there is a single, easy answer to these problems.