Need a real estate agent or appraiser's opinion

[Nolo]

House is about 2,000 sq. ft.  Currently 3 bedroom 2 bath.  Average home prices in this area is $85-90 per square feet.  (It's in the southern US, where home prices are incredibly cheap.)   Bonus room above the garage which is 400 sq ft.  This is almost completely unused except for the kids to just trash. 

Idea:  Convert the bonus room into two bedrooms.  Possibly add a bathroom.  This would make the house 5 bedrooms and 2.5/3 baths. 

After doing this conversion we will likely live in the home for 3-5 more years, at which point we will sell it.  Will this increase the value, decrease the value, or keep it the same?  By how much roughly would it increase/decrease the value?  Common sense tells me it would increase the value of the home but, I want verification from someone that knows the industry.  Most homes in this neighborhood range from 3-4 bedrooms, with the occasional and somewhat rare 5 bedroom. 

Any concerns I should have that I haven't considered from a marketing point of view? 

[Nolo]

House is about 2,000 sq. ft.  Currently 3 bedroom 2 bath.  Average home prices in this area is $85-90 per square feet.  (It's in the southern US, where home prices are incredibly cheap.)   Bonus room above the garage which is 400 sq ft.  This is almost completely unused except for the kids to just trash.  

Idea:  Convert the bonus room into two bedrooms.  Possibly add a bathroom.  This would make the house 5 bedrooms and 2.5/3 baths.  

After doing this conversion we will likely live in the home for 3-5 more years, at which point we will sell it.  Will this increase the value, decrease the value, or keep it the same?  By how much roughly would it increase/decrease the value?  Common sense tells me it would increase the value of the home but, I want verification from someone that knows the industry.  Most homes in this neighborhood range from 3-4 bedrooms, with the occasional and somewhat rare 5 bedroom.  

Any concerns I should have that I haven't considered from a marketing point of view?  

Southern US what part? and there are reason why some southern states are dirt cheap...Crime/no jobs/economy Etc.

No.  Dirt cheap as in compared to the rest of the country.  Absolutely 0 crime rate here in this town.  One of the best economies in the country.  Nashville suburbs.  

[Nolo]

House is about 2,000 sq. ft.  Currently 3 bedroom 2 bath.  Average home prices in this area is $85-90 per square feet.  (It's in the southern US, where home prices are incredibly cheap.)   Bonus room above the garage which is 400 sq ft.  This is almost completely unused except for the kids to just trash.  

Idea:  Convert the bonus room into two bedrooms.  Possibly add a bathroom.  This would make the house 5 bedrooms and 2.5/3 baths.  

After doing this conversion we will likely live in the home for 3-5 more years, at which point we will sell it.  Will this increase the value, decrease the value, or keep it the same?  By how much roughly would it increase/decrease the value?  Common sense tells me it would increase the value of the home but, I want verification from someone that knows the industry.  Most homes in this neighborhood range from 3-4 bedrooms, with the occasional and somewhat rare 5 bedroom.  

Any concerns I should have that I haven't considered from a marketing point of view?  

Southern US what part? and there are reason why some southern states are dirt cheap...Crime/no jobs/economy Etc.

No.  Dirt cheap as in compared to the rest of the country.  Absolutely 0 crime rate here in this town.  One of the best economies in the country.  Nashville suburbs.  

I would do more research then. If there is almost zero crime and in a decent neighborhood there must be a reason for such a low price. Disclosure is your best friend in this case. Real estate agent must disclose problems with the house/property.
How long has it been on the market?
foundation solid?
Roof solid?
electrical system up to date?
Plumbing system working?
Liens on property?
Radon gas tests performed recently?
So many Questions to ask.
A Radon test failure would make the house go dirt cheap and only make it a land sale.
ASK questions ask LOTS of them.

I think I confused you.  It's my house.  I've lived here for 10 years lol.  There's nothing wrong with the house.  This is what houses go for in this area.  And its a nice, all brick home in a great area.  You must be from the west coast or the north east  

I'm just looking to see if going from a 3 bedroom to a 5 bedroom and losing the bonus room would make financial sense. 

[Nolo]

Lol ooooooooo i thought you were buying!! lol
Yes i'm from the north east Massachusetts. I'm no Real estate agent but i own my home and upgrades are fantastic for added value.  up here 5 bedrooms is a bit Excessive 3 bedrooms is the norm.

upgrade the garage is a + though you could always rent it out or boot the kids out for privacy

I just wonder if converting a bonus room into two bedrooms would be considered an upgrade.  I'm sure some people would like the bonus room (since almost all houses here have them), but our living room is a very open concept, and I think that still provides plenty of living space.  Like I said, I can't even remember the last time I got my wife to climb the stairs to come into this bonus room.  It's my kid's own personal space to trash, and I'd like for us to get more use out of it.  Plus, that would allow me to turn one of the bedrooms into an office  

I also have to figure out how much the conversion would cost.  I'm talking to a contractor about it this weekend. 

[dogechode]

Is the garage attached to the house I assume? Or is it a separate structure with a separate entrance? This will have a bearing on whether it is viewed as a part of the home or a separate "apartment" ie rental income.

[Nolo]

Is the garage attached to the house I assume? Or is it a separate structure with a separate entrance? This will have a bearing on whether it is viewed as a part of the home or a separate "apartment" ie rental income.

Its an attached garage.  The stairs to go up to this bonus room come off of the living room. 

[dogechode]

Have you talked to local realtors? That would be the first step I would take... you could also post on biggerpockets and ask about this, ideally with a few pictures if you are willing to do so.