Attic Conversion - Making It Liveable

11 months ago

Hi Everyone -

Appreciate any input/feedback you can give on this attic conversion I'm considering.

I purchased a great home in Western PA last year that was originally built in 1926. It’s three stories, with the top floor being a finished attic space. We recently completed a nearly whole house renovation and tackled every floor other than the attic space, which is next on our list. The attic space is large enough to form two bedrooms. It's currently finished, but was poorly done.

The current finished attic gets INCREDIBLY hot in the summer. I’m talking easily +90 degrees on hot days. I haven’t been up there on single digit days in the Winter, but I’m sure it gets cold as Hell in there then as well. There are windows on each side of the attic and I’ve tried putting window units in each one during the Summer, but they don’t make a real difference. The rest of my house has central air, but the second floor won't cool because the heat in the attic can get so high.

The house has a slate roof, no gable vents, soffits or ridge vents. The only ventilation that I’m aware of is a mounted vent on the roof that seems to be controlled by a thermostat. There's a switch for that fan in the attic. I have no idea where the thermostat itself is located though. It seems like it may turn on when the heat gets to a certain degree. The attic has kneewalls and no ductwork.

If I were to “re-renovate” this space - meaning, completely tear everything out of the attic and start over - what should I do to make sure the space if liveable from a thermal perspective? Is there a particular type of insulation system or product that would work best for this situation? I'm not able to run duct up there, so I'm planning on installing a dual mini-split (handlers in each room) once the space is finished.

If helpful to know, the home is brick, with lathe and plaster throughout.

Thank you!

Comments (7)

beesneeds
11 months ago
Get in a heating and cooling person. They should be able to help you get ventilation in, sounds like you need it. Depending on what you need to get installed that might include a bit of roofing if it needs to vent out that way. It might be able to be vented out the side or something too. They will also be able to help with heating and cooling options. If the attic isn't insulated, get it insulated. Depending on your ceiling heights, you can install ceiling fans to help move air.
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Charles Ross Homes
11 months ago
It's a safe bet that your attic living area is subject to significant radiant heat gain. A vent fan isn't an effective way of dealing with that. You'll need to insulate the underside of the roof deck and do so in a particular way. I suggest maintaining a vented air space behind the slates incorporating both soffit and ridge vents. I'd install furring strips to create an air space, then install rigid foam insulation air sealed to the rafters and supplemented by spray foam to provide the required R-value for your climate zone.

If you plan to use the space for bedrooms, keep in mind that the window(s) in each bedroom will need to meet code requirements for emergency egress and the floor structure will need to meet code requirements for sleeping areas.
Stephen Perkins thanked Charles Ross Homes
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putting foam sheathing doesn't do anything but insulate the storage area flooring. it is a waste of time money and effort. in adding foam sheathing you are adding a vapor on top of the batts/blown insulation. batts actually work better on slopes because it is the uniformity of the insulation. as you will see, the blown will vary in depth in this area. it would behove you to get up into the attic before they finish and take a look. ask the R-value per inch of whatever blown insulation they are installing. figure out how many inches need to be in place to achieve this quoted R-value. take a yardstick or some form of measurement and measure the depth of the install in several areas. or ask them to do it while you shine a light to see if the depth is reached. any low spots should be filled. blown settles so depth should be a few inches over quoted inches. types of insulation have different qualities so some compacts (settles) more than others. if they are using cellulose..the air sealing is more important than ever.cellulose has a fine dust that will enter thru the smallest of areas. the bath fan for instance has openings in the housing. the cut where it fits thru ceiling is oversized. this cut should be sealed with mastic tape. back draft damper should be properly installed and vented out of insulation..perferably out of attic. the sloped ceiling is another place that will de-rate the overall R-value of the install. as are each recessed light (1 unsealed IC light = 1 sq ft of uninsulated attic space) you can see by the dirt on the batts how leaky the can lights are. if they don't address them from in the attic you may be able to install an ICAT insert and trim from inside the house. expect to pay $15 for insert, plus trim. you will need to brand name and model number of the recessed light. once you retrofit them use cfl's for more savings. if the attic is 1200 sq ft, and bid is for 944 sq ft, then 256 sq ft is the storage... I guess. I don't know what your starting out R-value is or what they plan to install. but as an energy rater (note rater not auditor) we have to deduct for areas like sloped ceilings, recessed cans, storage areas and all areas that have less insulation than overall. the attic staircase when not properly sealed and insulated derates the insulation install, and air leakage from this and recessed cans further are also penalties. I'm learning that these are some of the many differences between raters and auditors..and when utilities are involved in providing work for auditors and incentives the quality of the audit/rating is in question. if some company is paying a portion of your fee, you are not unbiased and working 100% for the homeowner. I've found hvac companies to be bad at sealing their own work.. best of luck.
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No there is not 7feet of headroom. I understand that this not "Legal" but I am not really worried about that. Living space is really ways a way. if I go down that road I would find an engineer to look at it. Storage space is really the main objective. I find it hard to believe that with 2x4's and 3/4" is NOT sufficient. I mean I stand on the rafters now and I am 200lbs. I know I know weight distribution over time is different than momentary impact. What is the best way to shore up the joists to make them stronger? thanks
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ok, I'll be less cryptic. 1st, I'm no expert. 2nd, I do know that an equal amount of air has to come inside as goes out the vent hole. 3rd, it seems you are in a climate that makes you want not to lose the conditioned air (which is understandable to me). 4th, I would arrange for an equal amount of unconditioned air to be pumped inside and sent to a grid rimming around the cooktop or range, and let that air be "the chosen" air to be pumped out of the house. This is because I always feel comfortable building my own apparatus to achieve my goal. If you are the same, and you make your own air curtain, in so doing you isolate the rest of the kitchen from the fine grease particulate matter that spreads everywhere whenever a bit of grilled salmon smoke rises up and escapes the hood canopy capture area. An air curtain curtails air movement. It directs the rising steam and grease particles to continue rising in a straight line to the canopy. You create a stream. You pull air in and you pull air out. One motor (blower) for each. The unconditioned air makes a funnel around the cooking surface and channels rising air to follow it to the hood canopy area and get pulled out of the house. Without this channel, the air that gets pulled out of the house can come from any direction and that lets rising steam and grease rise up and slip away in the opposite direction. Very disorganized. HTH
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Jim, reach out to a few architects. They all work with engineers or engineering firms for structural calcs, but it is the architect who will figure out how to fit it all together in a useful manner. The architect is going to want to design the whole thing for you. I would ask them to price it both ways (just staircase, and a full layout). Having just completed an attic conversion (and acting as GC and designer for it) I can say having it professionally designed would have been really nice
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res2architect
11 months ago
photos?
DeWayne
11 months ago
last modified: 11 months ago
You probably need to have it be an unvented attic assembly, rather than a vented one. To get proper insulation into an attic often involves reducing head space, to get enough R value, which makes it go below code minimum height. Insufficient insulation also makes it not achieve code as well, but is more difficult to see or enforce.
millworkman
11 months ago
Also need to be certain that the loading is adequate. Most attics are not framed (floor system/ceiling joists) with the idea tha this will be turned into living space. Unfortunately the time to investigate this and plan it should have been before you remodeled the lower levels as you may need to rip the roof and second floor ceiling to get to the mandated code compliance and make the "attic" safe.
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Charles Ross Homes
11 months ago
"You probably need to have it be an unvented attic assembly, rather than a vented one." The converted attic space will need to have insulation in the sloped portions under the sheathing/skip sheathing. While ventilation isn't always required, for example, when spray foam insulation is applied directly to the underside of roof sheathing, my guess is that there is nothing between the slates and the sheathing. In that case, you'd need to allow for drying to the interior or risk rotting the sheathing. A vent channel the full width of the rafter bays does that. It's the most forgiving assembly and it allows for an easier replacement of the slates in the event they are installed on skip sheathing versus spray foam applied to the underside of the skip sheathing and slates.
res2architect
11 months ago
Not enough information. We need the following:

- a section drawing through the attic space showing the span, size and spacing of the floor joists as well as the size and spacing of the rafters and the ceiling heights.

- a floor plan showing the dimension of the spaces.

- ceiling heights where different from what is shown on the section.

To save time and effort you could start with the joist and rafter information in case they're not adequate for the intended loads.

You will need all of the above listed information when you apply for a permit.

Attic Conversion - Making It Liveable

Comments (7)

beesneeds

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