Should I expand the basement into a third unit?

Question

Originally the basement of my duplex was designed to encompass a third unit but was scrapped for some reason.

Everything is framed, just needs flooring, walls and appliances. Where would I start with this? I assume I will need permits etc. Can you give me an outline of how to do this?

Thank you

David Krulac · Answer

@Justin B.

I'm not a big fan of basement units nor of finished basement, especially when they are below grade and the only exit is up the stairs through the house.

The dark, damp, musty, basement is not my idea of either an apt or a family room.  And there are often water issues with high water tables, rainy weather and malfunctioning sump pumps.

Of all the properties that we have only one has finished space in the basement and that existed before we bought the property.

David Krulac · Answer

@Justin B.

Perhaps the reason the basement project wasn't finished is because it didn't meet zoning/code requirements.

That's the absolute first place to check, as @Jon Holdman says, and you don't need finish plans just some idea on what you want to do.

Basements tend to be damp and cooler temps. A common heating system is sometimes a problem as the basement is too cold and the upstairs is too hot, both in the summer and winter.  Its a problem with central air also.

You want to make sure that all fire codes are met and there there is no liability of somebody being hurt by a basement unit that doe not meet code.

Jon Holdman · Answer

No, egress windows do not need to be 7' high.  They need to have a minimum of 5.7 sq.ft. clear opening with a minimum width of 20" and a minimum height of 24".  Maximum sill height off floor is 44".  For a basement egress window, the window well must be at least 9 sq.ft. and at least 36" projection from the wall with the window.  A permanent ladder is required if the well is more than 44" deep.

However, I'm referring to IRC 2006 and there are other codes in use.  Other codes may have other requirements. A 7' height doesn't make sense, though, given standard doors are only 6'8".  He may have been referring to ceiling height.

Justin B. · Answer

Jon your lengthy replies are much appreciated. I said 7ft because I saw a show on HGTV where they were converting a basement and the guy kept saying egress, sliding window is a must and 7ft of height.

I will go online and check it out.

Thanks

Jon Holdman · Answer

I would start by researching zoning for your property.  Most cities have maps online.  Or you could call and ask to speak with a planner.  You might need to make an appointment.  No need for plans, just have a discussion about adding a third unit.

Not sure what you mean by 7' egress standard.  The link I posted is for windows.  Bedrooms are required to have egress windows.  The easiest way to meet this is with a 4'0" x 4'0" sliding window.  But there are other choices and additional requirements.  The linked document (and the code books) cover all the specifics.  If this was an old unit it may well be grandfathered.  But since you're wanting to do new constructions you will have to conform to current codes.  A project like this may also have ripple effects elsewhere in the property for code compliance.

You may well have to hire a general contractor to pull permits, even if you do some of the work your self.  I would around here, for a rental.  I can pull permits only for a property I own and live in.  I have installed egress windows.  Its not an unusual thing to do around here.

Justin B. · Answer

Thanks for the replies guys, Jon do I just go in and start a conversation? I dont even have the building plans.

Is 7 ft the egress standard? Does code require a window for a lower unit?

Thank you,

Andrew D. · Answer

Hi Justin,

This is my first post ever, so I don't claim to be an expert - but I've looked into an additional unit in my basement also.  First, I would make sure your house is zoned to have the additional unit (3 units).

In NYC where I live, I believe you need permits when you are changing the structure of the house - for instance: adding a new electrical outlet, new piping, new wall structure.  I'm not sure if you need permits to sheetrock, tape, sand, prime, and paint an existing framed wall, or add a sink to pipes that already exist, etc...  If you look at the building plans of your house, and the C of O to see if there were any permitted changes to the original plans, you will be able to see what is already permitted and what you will have to submit to the city (additional structural changes).

Separately, water seepage is crucial to the decision to add another unit in the basement.  If there is any water that comes through the foundation or anywhere, then when you put walls up and the water seeps and sits behind the walls - you will have mold eventually.  You need to make sure the basement is completely dry before moving along.

In terms of the order of the items you listed above: walls first, then floors, then baseboards to cover the gap between walls and floors, then appliances.

I hope this helps, and if anybody can expand or clarify on my points - I would appreciate it.

Thanks

Andrew

Jon Holdman · Answer

First, does the zoning allow it?  Many areas allow duplexes but nothing larger.  If this is the case, you have a huge hurdle to overcome.  Could be the case in your area based on what you wrote.

Yes, permits will be required.  That will typically involve both a building department review and a planning and zoning review.  You'll need to draw up some plans.  The level of detail and precision depends on your building department.

Egress is often an issues with basement units.  Be sure you know the rules regarding egress.  Here's a link.  I checked this against my copy of IRC 2006 which is commonly used around here.  I recommend buying a copy of whatever code is used in your area.

If all this work was done some time ago it may not be fully compliant with current codes.

A good place to start is a discussion with the planning and zoning commission.  If they're OK, move on to the building department.