Why is that Bonus Room so Hot? So cold?

An add-on… a bonus room can be a nightmare with uncomfortable temperatures here in North Texas. Did we get the name right? Maybe you know it as a FROG – Finished Room over the Garage… It doesn’t have to be over the garage, you can cut into the roof line and add on in back, on the side, or over the top.

These often end up hot and uncomfortable- especially in hot hot weather or during a cold blast during the heating season. You probably have a pretty clear idea of the issue if you are searching and found this page. Let find out what is happening and what can be done about it. You deserve better.

There are two main reasons there are heating and cooling problems and they are related.

We can pretty much lay the blame at the feet of the remodelers out there or the person who hired the remodeler. Remodelers get put in a tough position. We call them when we want new stuff but we always want bargains. We like to pay for stuff that makes the house pretty or more useful or look new… and we want the most sexy good looking that we can get for our dollars. This is a pressure also shared by builders. I am not making excuses for either but… we talk about buildingers and remodelers here. LINK

bonus rooms can be hot and uncomfortable. Is yours?

Do you have a nook or a remodeled bonus room that is too hot in summer and too cold in the heating season?

Secondly, add-ons and bonus rooms and FROGs are cut into and added to the existing structure- the garage or the attic line, and require modificaton of the existing structure and custom design to fit properly.  The new spare room, is tied on a bit haphazardly, to fit in. This can leave you with non-standard transitions and unique intersctions of new and old materials.

Lets look at an actual detail of the structure.

Kneewall in Remodeled Space

Knee walls are used to take back space from pitched roof areas. This creates several design issues which must be addressed. See text below.

The diagram above shows several design factors which must addressed if you want to capture space in a pitched roof attic. Knee walls are the component which allows this. The rafters shown here must now be modified to allow continued ventilation to the peak of the roof from the soffit vent shown at the lower right and the insulation for the add-on. Now this is a particular layout here and not typical of all bonus rooms and add-ons;but the principle is the same. You are changing the basic functions of the building and to have a successful remodel you must reconfigure all these components into a new functioning order or you will have issues with too hot and too cold. And not only too hot or too cold. Screw up the ventilation and create a lot of air leaks and poor insulation into the the new weathering layer under the roofing, and you have all the ingredients needed for moisture problems and rot and mildew and structural failure.

These same  sides  and roof of the add-on spare bonus room are adjacent to the hottest part of the house- the roof. While the potential for problems quadruples, the attention to details falls down because the details are custom designed on the spot by someone working quickly with the materials they brought with them. Add-ons and bonus rooms end up with poorly designed details poorly executed, because all parts of the adding are being cobbered on to the existing.

Bonus rooms are cut into and patched together from what is there. The remodeler at any one moment is figuring out how to make a structural transition to make the structure fit and be sound construction. These are custom details and you are working with trades people who are  in a big hurry- hot and thirsty probably,  who brought the materials they thought they would need with them.

Remodels have an ad hoc quality that home construction does not. New homes are built from scratch, and when all goes well, the details are what you expect when you show up as a sub- contractor. When you show up to work on the remodel, you get to figure out where the electrical connection will be, where the plumbing connection will be made, and where the cooling air will be tied in.

This is a recipe for cooling and heating issues, as we need our remodeler to pay close attention to air leaks and insulation, and balanced delivery of air conditioning. What has happened instead, since you are hear reading this, Is that the air barrier does not exist or has some big gaps, and the insulation is skimpy with lots of gaps. The combination of being closer to the hottest parts of the house, shrinking the ventilated area of the attic, and the size of the space putting you closer to all these radiation sources and then a huge potential for falling down in the details which would make a great air barrier and insulation layer are compromised… well, you are here.

We must revisit the idea of  conditioning this add-on space All the things that can go wrong with delivery of air in a standard attic can go further eschew in the add on.

Now on top of that you can also get a local handyman – remodelers helper- remember we are not gold plating this- we want to save money- shows up with flex duct and a pair of tinsnips and you can end up with any combination of the following screwups possible in creating ductwork, and any combination of screwups can leave you way to hot to work or relax.

  • poorly placed hole in the plenum
  • flex duct laying in lazy loops and laid out properly
  • scant attention paid to return air
  • poorly sealed joints that leak
  • poorly insulated boots that leave the duct shell below dew point during parts of the year.

you don’t have to suffer from all these to have issues, just one or a combination. These mishaps happen all the time, and they show up when the moisture issues have a chance to develop and grow or the extremes of temperatures come along and overwhelm you. We discuss mechanical defects which can cause you discomfort- in detail here. LINK

And these mechanical issues are working in combination with any air sealing and insulation issues built in. You have good reason to feel battered. You need fundamental help here. Not more cooling power added on. You need to find your existing issues, and fix those. That takes a trusted professional. We talk about find your selected professional here. LINK

The lesson of construction is that only the most conscientious take the time to do it right and this is only done- when the owner has explicitly understood the construction process- wants the job done with care at all times- has a professional inspector or architect keeping an eye on areas requiring clear detailing to get the details done with care.

Do you feel I am overstating the case here? Maybe. Please do not let me overstate specifics here that do not match what you have experienced or that you want to do. Each home has it unique details. Each home needs clear detailing designed up front to make sure you end up with sound construction but also that your air control layer and your insulation barrier has not been broached.

If you are contemplating a remodel, concentrate on sound construction and not on cutting costs. If you feel this is an understatement, traipse on over to hobb.org

[textbox] Here are specific resources here.

This subject relates closely to

  • these notes are complemented by discussion of all issues relating to too hot too cold spaces
  • issues with the upstairs being to hot
  • here is another link to the mechanical issues discussion
  • your bonus room can also impact your health
  • here is a broader discussion or remodeling and contractor issues..

What can you do? What do you want to do?

You have what I would figure are two choices here unless you have a trusted construction advisor, and would you be in this spot, if you had that?

I would address this as wanting to understand the true causes of your predicament with the addo-on and understand your options for fundamental repairs. You do not need treatments of symptoms. You do not need more cool until you figure out if all the other issues are under control.

You need to get more familiar with the role of the home energy auditor. They can profide clear and unambiguous data to your situation using a variety of testing equipment. Their thermal camera- in the process called thermography can take some images of your heat flow problems and make some suggestions for you.

Or maybe you know a great HVAC service company that is moving beyond the traditional role of installing cooling boxes and transforming into a home  performance company. The role of the future HVAC company dealing with home performance issues and your home energy rater will get closer. We need to understand building science before we can make smart choices in design, in retrofit and in installation of new equipment.

We have a great discussion of the process of finding the professional you are most comfortable to deal with serious comfort issues here.

Any thoughts, any questions? any comments. I play pretty rough here on builders and remodelers. Most of them deserve a few slaps but their are some very good ones. We just have to be able to pick out the good ones and not be infatuated with the special deals and offers of the mediocre. Here is a LINK  to what to avoid…  this little riff there was sort of like a PS…


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