Finishing Attic Above Garage - Cost Estimate?

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Old 03-14-16, 11:23 AM
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Finishing Attic Above Garage - Cost Estimate?

Hello,

I have an attic space above our garage that is approximately 400 square feet. It currently has plywood flooring for storage and that's it; the rest of the attic is unfinished.

I'm considering finishing the space for an office and am looking for a rough estimate on costs to DIY a project like this. I have plenty of helping hands for any of the carpentry/sheetrock details, the only portions of work I'd be outsourcing is plumbing and electrical.

I am looking to do this project as cheaply as possible while still doing it properly and up to code. There will be no expensive additions such as bathroom, hardwood floors, etc. None of those are included, this is a basic remodel.

Since the space is above the garage, I'm assuming there will be special needs for ventilation to ensure no fumes get in. The main entrance to the new space will be from the second floor (new door to be put in through one of the bedrooms that abuts the garage attic).

For insulation, R30 is common in our area.

What I'm looking for is a rough ballpark estimate on bare minimum costs. I realize a lot more info is needed for an accurate quote — I only need a basic guess on costs right now. For example, is this a $5k to $10k project or much higher?
 
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Old 03-14-16, 01:20 PM
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Talk to your local permit office to see what they will need and verify what work you can do and when. Each phase of work may require an inspection and you don't want to go too far and hide something they want to see, plumbing, electrical, framing, heat, and insulation.

Local requirements vary greatly up here so hard to judge what you will need. My guess is your budget numbers are a bit low. Meeting our new energy codes is important and doing it with a sloped roof can cost extra. Below are the 2009 IECC insulation requirements.

In addition to proper drywall on the garage ceiling you may need to drywall the entire garage.

Depending upon how they classify your improvement they may want more. Choosing to use it as an office doesn't mean it won't be used by you or a future owner as a bedroom.

Best,
Bud
https://energycode.pnl.gov/EnergyCodeReqs/?state=Maine
 
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Old 03-14-16, 02:51 PM
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Finish Attic

A major concern would be whether or not the ceiling joists in the garage are sufficient to support a living space above.
 
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Old 03-14-16, 08:12 PM
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Thank you for the great info, this is very helpful.

Regarding the drywall, the garage below is already finished.
 
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Old 03-14-16, 08:16 PM
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Thanks for the feedback and I do believe the joists are sufficient. They are 2x10's every 16".
 
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Old 03-15-16, 06:00 AM
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Joists Span Length

Thanks for the feedback and I do believe the joists are sufficient. They are 2x10's every 16".
What is the span length?..........
 
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Old 03-15-16, 07:36 AM
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Total garage/attic width is 24'. There's a center beam (three 2x10's nailed together) so span for the joists is 12'.

Let's not get too focused on one aspect of the project, only looking for ballpark estimates at the moment. Thank you.
 
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Old 03-15-16, 08:08 AM
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I understand what you want, but there are so many details missing it is impossible to guess beyond what I gave you, your project will be more than the high number you quoted.

Example, are you going to pull a permit and follow all building codes. Many who post here just want to do things their own way and sneak by without inspections or following the codes. Tell us you want to follow all the rules and the price goes up $10,000, because there are a lot of rules.

Another example, you probably have 2x6 rafters (we have to guess) and you cannot install the required insulation in that space unless you switch to a hot roof with spray foam, very expensive. The alternative is to pad those rafters to allow space for the required insulation and ventilation channel.

Will the town consider this a bedroom, more requirements?
How will you heat this space? Add on to your existing system (unknown), install a separate system, or just use the most expensive heat source for us, electric heat.

Don't get upset at us for digging through the details, that is something we have to do all the time. But even then, about the best we will be able to do is give you a help on how to do this so you can ask better questions from a local contractor.

Are you closer to Kittery or Fort Kent, coastal area or up in Jackman? Big difference.

Bud
 
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Old 03-15-16, 06:03 PM
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No problem at all, thanks for raising more good questions (answers below). I understand it's impossible to give an accurate quote from a forum post but feel free to keep asking me for the info you need and hopefully we can narrow down a closer ballpark estimate.

Regardless of what other forums members say/do, I am planning to follow all building codes. I will be doing any manual labor I can to save costs, like sheetrock and flooring, but anything beyond that (electrical, heating, etc.) I'll be hiring professionals for.

Rafters are 2x8.

I'm not sure how town will classify the room, good question and I'll research. It will be used as an office.

For heat, there are baseboard hot water heaters that abut one end of the attic in a neighboring room. I'm thinking I could have a plumber extend that piping into the new attic space. That'll be a question for the plumber. If they don't like that idea, I'll have to find a separate system (non-electric).

Location is closer to Kittery.

Thanks again for your time.
 
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Old 03-15-16, 08:33 PM
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Going with permits and following codes is by far the best path, very good.
I'll be short.
1. Your 2x8's will be borderline for a 12' span. Others here are better at those details. Not sure if the verticals at a kneewall location will help with the span, seems like they should.
2. Slope of roof and inside ceiling height? There will be a minimum height and a % of area for that ceiling. Something like 7' and must cover 50% of the floor area. But I don't know what Maine requires with their new codes.
3. The 2x8's also create a problem with meeting the minimum r-30 for the floor. Can be done in 7.5" but will require more than just filling with batts.
4. For the sloped ceilings there are % area factors which I do not know whether they apply to the entire house or just the garage. Probably just the garage as the house may not meet the new code requirements. You will need to determine your required r-value and then decide if you want to pad out the existing rafters enough for insulation and ventilation or just enough to fill with spray foam and eliminate all ventilation.
5. Check egress requirements.
6. Plan on 2x6 for kneewalls if installed.

Bud
 
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