Basements (4 of 9): Insulation

Insulation in the basement seems like a foolish thing to do.  After all, what could provide better protection then a very thick and heavy wall?  The truth is that concrete has one of the lowest values of insulation.  In fact I am certain that everyone who has spent time in basements has noticed a drop in temperature.  This is not merely because it is below grade.  This is the result of poor or no insulation.  The basement is a conditioned space and should be comfortable just like the rest of the house.

 Insulation values are rated as R-values.  The higher the R-value, the better the insulation.  Current energy code requirements state that exterior walls must have an insulating value of R-19 or better.  This is so the expense of heating a home is not lost (or at least is greatly reduced) due to thermal failure in the walls.  The same should hold true for basements.  One should not “put up” with the discomfort of a chilly basement simply because that is the way it has always been.

This brings me back to R-values.  Standard Batt insulation for a 2x6 exterior wall has a value of R-19.  Compare that to concrete which has a value of R-0.08 for every inch.  For a typical basement foundation wall of 8” that is a total value of R-0.64.  YIKES!!  Why wouldn’t you want to insulate your basement when so much energy is being lost through the walls?  The best way to prevent this loss is to provide furring (built-out framing – more on this in a future post) at the perimeter wall and fill the cavities with insulation, just as you would any exterior wall above grade.  The expense will be well worth every penny when you can spend every moment in your basement in comfort.

Basements (3 of 9): Head Clearance

With how frequently basements are finished in Colorado, it is odd to me that there seems to be very little forethought regarding their function when the home is designed.  Often there is a great deal of tweaking and adjusting required to make the spaces work. 

One thing that must be considered is head clearance.  In order for a basement to be considered habitable, most municipalities in the Denver region require a minimum head clearance of 7’-0” throughout the entire area proposed for living space.  This can be a challenge in older homes when the basement (or cellar) was intended only for coal storage or other utilitarian functions.  Some municipalities also stipulate that only a certain percentage of the ceiling in each room can be permitted at 7’-0” (or whatever their regulations require).  With the use of dropped beams this can be a serious challenge even in newer homes.  The key is to do some pre-planning research so you don’t have to pay for costly redesign fees.  Of course, most architects and residential designers will perform this task before a pencil is set to paper.

The next consideration is head clearances at doors or doorways.  The code requires that all doors, doorways or openings intended for passage are to be a minimum of 6’-8”.  Some municipalities allow for exceptions in finishing basements, again, because of the standard and common use of dropped beams.  Others are more stringent and will not allow for this exception.  This could be a real issue and must be addressed before any design work is to be considered.  This is also something that can easily be overlooked in design review and create major problems during inspection.  At that point you are entirely at the inspectors’ discretion, which is not always in your favor.  Planning ahead and placing doorways away from dropped soffits and beams may be inconvenient, but it could save you a lot of headache and expense later.

Even with the challenges of designing around beams, the basement can add some much needed space and function.

Basements (2 of 9): Egress

Egress is a term that is used heavily within the building and construction industry, but for most outside of this field it is just a funny sounding word.  Simply put, it is the means to exit a building.  This is important in residential design, especially in bedrooms and basements.

The first thing to understand about egress requirements is that even though it is important to provide a means to exit a building, it is more important the opening is large enough for a firefighter to enter the building while carrying all their necessary equipment.  This is why within the building code there are many stipulations regarding the minimum dimensions and location of openings in any given room. 

Some, even within the industry, mock some of these regulations.  For example, a casement window (windows that are hinged and open with a crank from the inside) have minimum dimension requirements based on the open position of the window.  The standing joke states that the firefighter must first break the window and then crank it open to gain entry.  The truth is that if there is a fire and the window is already open then the clearance must be adequate for proper egress and fire rescue.  Although some code requirements seem mockingly hilarious, there is a legitimate reason for the code and it could be the one that saves your life.

Since the access to most basements is a stair leading from the main level of the house, how this translates in basement design is that a means of egress must be provided from each bedroom and the main living area which leads directly to the outside.  The sill of an egress window must be within 42” above the finished floor (and I would argue this should be lower for rooms intended for smaller children).  There must also be a permanent ladder secured to the side of a spacious window well.  To most people the first image to come to mind is an ugly, pre-manufactured, corrugated steel well with a matching hideous ladder.  This need not be the case.   As long as the well meets the minimum dimensions and stepping is provided that does not exceed required dimensions, then the sky’s the limit on possible well design.

So, since you have to have a window well, think of all the possibilities to personalize it and let the design become a feature of your basement and not something to hide with drapes or the dreaded blinds.

Basement Finishing 101

With the economy taking it’s time to recover, and the Denver Metro area is as susceptible as any, many people are finding it necessary to make do with their existing homes instead of moving to a new residence.  One of the most common methods of increasing “space” in the home is to finish the basement.  Through the next several posts we will help you understand what is involved in basement finishing and design, and how to create a lasting living space to enjoy for years to come.  We will discuss means of Egress, Head Clearance requirements, the need for Perimeter insulation, why it is wise to Consolidate Plumbing, the need for Treated Wood, Floating Walls, how to finish Exterior Walls and what to consider for Theater Design.   You don’t have to move to get the home of your dreams.