Last week we discussed the common problem of the uncomfortable bonus room and reviewed several reasons why it gets so hot. (To see last post click HERE) By popular demand, I am posting again to answer the question of, "what can be done about it". I will give the solutions to the four problems identified last time, namely "Attic Air Currents", "Attic Heat Buildup", "Attic Access Doors", and "Heat Rises".
1. Sealed Insulation: Because fiberglass insulation is porous it MUST be sealed on all six sides to perform at its maximum. When you look into most bonus room attics you will see that the insulation on the wall is exposed on the back, the insulation between the ceilings is exposed on the ends, and the insulation between the floor and the garage is exposed as well. If this is the case, air currents which are caused by the force of warm air rising, will be constantly moving across and through the fiberglass insulation greatly reducing its effectiveness. To solve this problem a proper air barrier needs to be installed to block these air currents. First, install a sheathing material such as a thin ply wood or dry wall over the back of your exposed knee-wall insulation. Make sure to seal each of the joints with an expandable foam or calk to create a proper air barrier. If you want to the very best results you can use a foam insulation board as your air barrier which will also add additional R-value to your wall assembly. Second, use the same sheathing material and cut pieces to fit in the cavities between the two floors and the floor joists. You can cut them a little small so they fit easily and use expandable foam to seal around the crack. Third, the final project is to finish making your insulation air tight by installing a card board stop over the exposed ends of your ceiling insulation. If you look at this insulation you should see a styrofoam baffle between the top of the insulation and the decking on your roof. This is to allow hot attic air to flow to the peak of the roof between the insulation and the roof decking and exit out your ridge vents. When installing your card board stop you need to make sure that it goes between the insulation and the styrofoam baffle and then folds over the end of the insulation. The goal of this stop is to block air currents from flowing through the insulation and direct them to flow through the space between the baffle and the roof as intended. Once you have finished these three steps your insulation will be able to function as designed and perform at is best.
2. Radiant Barrier: The best way to combat attic heat buildup if you have a properly vented attic is with a radiant barrier. This product was developed by NASA and reflects radiant heat. Radiant heat is the heat you feel when you step into direct sun light. When the sun hits your roof it heats is up, and it intern, begins radiating heat into your attic. By installing a radiant barrier across the air barrier covering your knee-walls it will reflect that radiant heat away from your bonus room. You can also install it on the underside of your roof rafters, as a second line of defense, to block heat from entering your attic. Properly installed radiant barrier combined with properly sealed insulation makes the best barricade against the summer heat.
3. Attic Door Insulation: If your attic doors are not insulated at all or if they are covered with some old fiberglass insulation, it is high time to properly insulate them. The best option is to use a foam boar product around 2" inches thick which will give you an approximate R-13 insulation level. You can also attach some of the radiant barrier to the back of these doors to reflect the attic heat.
4. Air Sealing: Although there is nothing that I can recommend to reverse the reality of heat rising, there are solutions to help limit its affect. Air sealing your home is the key. In order to understand how to properly air seal your home, you must remember that hot air rises and that for every cubic foot of air that escapes from your home one is replaced. These two realities mean that when warm air in your house rises to the highest point in the home and escapes through a crack or hole into your attic it is replaced by warm outside air from somewhere lower in your house like a plumbing penetration in your crawlspace. As this action occurs hour after hour it draws more warm air into your house and makes your AC system struggle to keep up. To stop this problem begin sealing all the penetrations you can in your attic and then begin sealing any other air leaks lower down in your home. When air sealing always remember "top down" because if you can stop an air leak in your attic it will block air that is trying to escape as well as keeping that air from creating a negative pressure on your house and drawing in warm air from somewhere else.
Hot bonus rooms are a hassle, but they don't need to get the better of you. These fairly simple solutions can revolutionize the comfort of your bonus room and make it a place that you actually enjoy spending time on these hot summer days. I know my explanations may be a bit confusing if you don't have a construction background so feel free to ask me any questions. If you don't feel like spending the time in your cramped hot bonus room attic to install these improvements, give us a call, and we can do it for you. Visit us at www.EnergeyesOnline.com