Duplex has thin walls

What is the name of your state? Alaska
Three month ago I bought a duplex as an investment property. I am currently living in one side and renting the other. After moving in I immediately noticed how "thin" the walls are. My tennant next door is not very loud but I can still hear every word she says when she is talking on the phone, literally! It is absolutly a problem, one that's never been a issue with my other properties. It will be challenging to keep long term tennants in any unit once I move out and want to rent both sides....potentially causing large losses in rental income. I feel that this should have been included in the discosure statement, especially since the seller was living in the side I moved into for the previous two years. Is there any action I can take? Could the builder be liable if the building wasn't built to code? The duplex was built in 1996. I appreciate your response.What is the name of your state?

There is probably nothing you can do about it now. It will be up to you to redo the common walls to dampen the sound transmission.

Since your living in the unit I agree with I O , you need to use a utility knife , open up one wall between the units to learn if there is any insulation at all , If you find none then go to your nearest lumberyard and get how to book / tape for drywalling and insulating and put in insulation in for the purpose of soundproofing. If your not going to do it your self then hire it out, which ever way you do it you should be able to write all or 1/2 of it off on your taxes against the rental income. Since your going to use this as investment property eventually this would be a nice project to do since it could help you retain tenants , besides the fact that it will help reduce heat loss between units. LAST you know since it was built so long ago fair odds are if you learned that some part of the units construction did not meet code it may well be pointless to try to go after the builder, its just been too long now, your legal fees could far exceed the cost of soundproofing between them. You are certainly free to discuss the matter with a atty for the best possible advice. Try the links up top if you wish to consult with a atty.

If your interior walls are typical stud & drywall, you can cut small holes in the top of the walls and blow in insulation between the studs. This is the same process they do in older homes with exterior walls to insulate from the weather, but you could do it on the interior walls for sound. It wouldn't be that expensive if you do it yourself, but it might be a little messy, plus you have to patch and paint the drywall. But it's doable!

I don't see how you could sue the builder unless he misrepresented the house in some way - like he said the interior walls were insulated against sound or if that is code in your area. The disclosure is to disclose know defects in the property. I wouldn't consider 'sound' a defect.

you can cut small holes in the top of the walls and blow in insulation between the studs. This is the same process they do in older homes with exterior walls to insulate from the weather, but you could do it on the interior walls for sound

This might muffle the sound a little but would not eliminate the problem by any means. If you are going to fix the problem fix it right, to protect the investment you have made, and go the sound board route.

I'll offer a couple of suggestions to reduce the sound flow between your units:

1. DIY - Fast and low cost. The most common causes of sound transmission between residential units are openings in the wall that act as air passages. These include:

a. Electrical, telephone, and cable TV outlets. To save time, builders and contractors often place these boxes adjacent to each other in common walls. In the most solid walls, you can hear a conversation on the other side through these openings. To stop the flow, remove the face plate (turn the power off, of course), use duct tape to seal any holes or missing slugs, and stuff some non-conductive materials in the back of the box. Be sure the face place fits flush against the wall. If not, put some adhesive backed weather stripping on the back of the plate to stop the air flow.

b. Examine where the walls meet the floors. Low spots in slabs and inconsistencies in the surfaces of tile result in a gap between the floor and the wooden "plate" that's at the lowest point of a stud wall. Sound floods right through. Though it's not as common in dry wall construction, this also occurs where the ceiling meets walls made of concrete block. Use a high density caulk to seal these spots. They're easy to find. On cold days you can usually feel cold air seeping through the cracks.

2. Insulate and resurface the walls. Several remarkable materials are available for installation on existing stud or concrete walls. These are very dense and absorb rather than transmit sound waves. Coupled with acoustic insulation, these can be very effective. This isn't a low cost alternative but it's much more cost effective than removing and rebuilding entire walls. I'm including a link below for a product called Acoustiblok. This page has some graphics to help you understand how to reduce sound flow between your duplex units.

http://www.acoustiblok.com/products.html

Good luck!