After having to re-plaster a portion of our ceiling in our dormer room upstairs, I noticed heat this summer pouring out between the lathe from the crawlspace above. We currently have no ventilation for this space and it looks like it never had. Our house was built in 1920 and we live in Cincinnati. A roofer recommmends putting two vents that allow air to escape on either end of the roof (on the back slant. -Our roof slants toward the front and back of our house.) I would like to know if this is the best way to vent before I let them cut holes in our roof. Thanks! <br> <br>Lisa <br> <br>

Lisa, Have you considered (or do you have room for) small shed dormers on the front & back? The vents for bungalows on the roofs were often low shed dormers. They would mimic the existing dormers and/or the existing eave & rafter tail details. This would involve a bit of work and additional expense but if done correctly would look original and add a lot of charm. A lot of these dormers had windows in them that opened or could be removed, not vents. I have removed the glass in the window frames and replaced them with screen for ventilation. Current opinion seems to be you want ventilation year around, at least here in California. <br> <br>John L <br> <br>

Hi Lisa, <br> <br>Whether you need to ventilate that area depends to a large degree on what has been done to your craftsman since it was originally built. <br> <br>Many older homes weren't originally insulated and had wood shingled roofs. Consequently, they "breath" really well. Meaning that they have a multitude of air leak sources and aren't very energy efficient. Many homeowners today will attempt to cut down on energy usage by blowing insulation into the unfilled wall cavities of these homes and packing insulation into the attics. This helps to save heating and cooling costs, but often causes moisture-related issues that the home never previously had. These issues oft-times lead to rot. <br> <br>Attic ventilation is one of the most controversial issues there is in Building Science. I moderate the Building Science Forum at the Journal of Light Construction website, and I can attest to the fact that no other subject engenders more debate among building professionals. However, there are some proven concepts that, when understood, will help you decide whether vents will be necessary. <br> <br>Have you insulated the side walls of your home with blown-in cellulose insulation? If so, cellulose is a very effective air stop and tends to force in-house moisture up into the attic through wall outlet and switch covers, cutouts for electric light fixtures, around unsealed attic hatches and through air gaps under/behind moldings. Without vents to remove this moisture, condensation can form on the underside of a cold roof in winter and eventually cause rotting of the sheathing. It could also be such condensation and accumulated trapped moisture that caused your plastered ceiling to fail. The moisture weakens the plaster, eventually causing keyway failure and allowing the weight of the plaster to pull it away from the lath and crack. <br> <br>Research has shown that a combination of air-sealing an insulated house, to remove all paths for leakage up into an attic/roof cavity, along with the use of vapor barrier type paints, can eliminate the need for attic ventilation completely. However, few contractor laborers today have the requisite knowledge base and skills needed to accomplish this task, let along homeowners. <br> <br>Are your ceilings insulated above that room? If not, the fact that it is very hot in that area and that heat is moving into the room below should not surprise anyone. An attic can get as hot as 130 to 140° in summer. This won't necessarily harm the house, since roofing materials are designed to be subjected to a certain amount of heat, but it can reduce shingle life somewhat if excessive. Heat naturally moves from warmer to cooler and will migrate into the room below unmitigated without insulation over the ceiling. On the flipside, without insulation above the ceilings this area has the potential for causing ice damming in winter in Ohio, as heat moving rapidly up into the attic melts snow cover on the roof and causes it to run down to the eaves where it re-freezes into an ice dam, causing additional melt to back up under the shingles. Adding insulation over the ceilings, particularly blown-in cellulose will help to mitigate some of the air moving up into that area, can reduce or eliminate much of the causes of snow melt and may reduce temperatures in the room below. This still won't eliminate the need for supplementary measures to either ventilate the area or provide better air sealing to reduce exposure to moisture migrating. <br> <br>Want to learn more about the effects of attic ventilation/non-ventilation? Visit the Building Science Forum as the Journal of Light Construction and read through some of the numerous past threads on this topic. Sorry, we ask that non-professionals not post to the forum, but it is free for everyone to read and, if desired, you can e-mail participants directly to ask them additional questions. <br> <br>Hope this helps a little bit. <br> <br>ONE TEAM - ONE FIGHT!!! <br> <br>Mike O'Handley <br>Bungalow Rescue, Seattle <br>hausdok@msn.com <br> <br>