Making basement deeper in Baltimore City

[Erick Chavarria]

I have a rental property that would benefit from an additional bedroom. The basement is currently 6'3" high. How complicated is it to dig another 12-18 inches in a section of the basement to be able to build a 3rd legal bedroom? The basement already has a back door plus two large windows.

Do I need to get a permit? 

Do I need to hire an Engineer or is this something a contractor can easily do without much complication? 

Basement doesn't have a sump pump, do I need to put one in? 

Thanks in advance for you help! 

[Eric Teran]

@Erick Chavarria first off, great name. I have done about 15 of these types of projects for my clients in the DC market in the last three years. It can become expensive but it depends.

1. Most important determine the depths of your existing footings. You can do this by digging a hole about 18”x18” and dig next to the party wall. Once there is no more brick or concrete then you have reached the bottom of the footing. Let’s say the footing is 13” deep then you subtract 4” for a slab and you are left with 9” of additional ceiling height. If you want to go lower than the footing then that will require underpinning and that may become expensive. Be sure to dig a hole on both party walls.

2. In addition to egress you need natural light to come into the space. I forgot the requirement but usually if you have an egress window or door with glazing it is enough.

3. If you drop the slab you may have to drop all your existing sewer lines. Theo will add costs. Especially if they have to be dropped all the way to the street.

4. Is there any mechanical or other equipment in the way to have a decent bedroom and space down there? This is where an architect may come in handy. In DC we are required. I’m not sure about Baltimore as I’ve only done a few bigger projects there like a full gut rehab.

5. To confirm you only want additional bedrooms and not a separate unit because that is an entirely different ballgame?

6. You will most likely need a structural engineer to ok drop the slab. You might be able to get away without an architect. Don’t let a contractor do all this on their own unless they have a structural engineer on their team.

Good luck

Eric