Building a second level on top of a house with 2x4s

[swimmer_spe]

In a few years, there is a plan of doing an addition. We either go out or up.
Going out means just adding a master suite with a walk in closet and an ensuite. It also means going down and adding a full basement. We gain some space, but I feel going up is better.
Going up would mean the master suite, plus at least 2 more bedrooms. Due to the reconfiguration of the main level, we would net gain 2 bedrooms.

We are in the middle of a bathroom reno and have discovered the exterior walls are 2x4s.This isn't surprising since the original part of the house was built in the 1930s. Our contractor has told us that generally, you cannot add a second floor unless there are 2x6 walls. Besides local laws, Does anyone know whether this would be true? It doesn't make sense since most homes were built with 2x4s.

 

[Snoonyb]

He may be saying that, to satisfy an insulation requirement, however those can be accommodated in several methods.

See IECC for you local; Residential Insulation | Codes and Standards, Compliance

 

[oldognewtrick]

Something to consider when adding living space, your age. Stairs are not friendly as we get older.

 

[Sparky617]

I would probably go out for the reason Oldog mentions. An older neighbor just did it to his house, up wasn't an option on his two story house. They want to be able to age in place and stay in this house as long as possible. They built a first floor master on their 3 BR house. They make accommodations to make it accessible. Theirs was a 3BR in a mainly 4BR neighborhood, and our neighborhood value has sky rocketed so they had plenty of room for increased value.

 

[swimmer_spe]

Something to consider when adding living space, your age. Stairs are not friendly as we get older.

The good thing about the addition, going up will not mean the loss of that ability. In fact, by going up, we could move our washer/dryer to the main floor.

 

[Sparky617]

The good thing about the addition, going up will not mean the loss of that ability. In fact, by going up, we could move our washer/dryer to the main floor.

With an existing first floor master going up would make sense. Even if you move your bedroom upstairs for the next 10-20 years and you used the current master as a guest room or craft room, or whatever in the meantime. That said, unless I had small kids, I'd probably keep my master on the first floor and upgrade the bathroom and add other bedrooms to the second floor. Maybe even taking space from the existing first floor bedrooms to make the master suite bigger.


You'll need an engineer to review your existing foundation to determine if it can handle the extra load. The 2x4 walls aren't really a concern. My two/three story home has 2x4 walls. The walkout basement framed wall on the back is framed 12" on center, but the first floor has 2x4s 16" OC. If I were further north, I'd go with 2x6 walls and maybe a layer of insulated sheathing.

 

[swimmer_spe]

With an existing first floor master going up would make sense. Even if you move your bedroom upstairs for the next 10-20 years and you used the current master as a guest room or craft room, or whatever in the meantime. That said, unless I had small kids, I'd probably keep my master on the first floor and upgrade the bathroom and add other bedrooms to the second floor. Maybe even taking space from the existing first floor bedrooms to make the master suite bigger.

There is no way to take the space of the other main floor bedroom to make the master bigger. Nor is it needed.However,due to the layout of the house, the plan would be our second bedroom would be converted to an outside entrance, stairs to the basement, and a laundry room. Right now, you need to duck to go down the stairs to the basement which will be a big problem as we age.

You'll need an engineer to review your existing foundation to determine if it can handle the extra load. The 2x4 walls aren't really a concern. My two/three story home has 2x4 walls. The walkout basement framed wall on the back is framed 12" on center, but the first floor has 2x4s 16" OC. If I were further north, I'd go with 2x6 walls and maybe a layer of insulated sheathing.

Since we are going up, we would be residing the house. That does mean we can add insulation to the exterior walls if needed. The house isn't horrible for warmth in the winter. When we removed some drywall, we saw that it was decently insulated as is.

 

[bud16415]

As others have said the 2x4 exterior walls 16” OC should be fine for the load of a second floor. There are many reasons for going up or going out pro and con. Most often going up is a result of not having the room to go out. Going up is very disruptive of all the living space during construction and would require unloading the house and you moving out during the building process. Going up opens the finished house areas to the weather etc.

My suggestion is if you have the area going out is what I would do and the benefit is the increased basement area that is the cheapest square footage in construction. The new area can then be framed 2x6 or whatever you like.

 

[swimmer_spe]

As others have said the 2x4 exterior walls 16” OC should be fine for the load of a second floor. There are many reasons for going up or going out pro and con. Most often going up is a result of not having the room to go out. Going up is very disruptive of all the living space during construction and would require unloading the house and you moving out during the building process. Going up opens the finished house areas to the weather etc.

My suggestion is if you have the area going out is what I would do and the benefit is the increased basement area that is the cheapest square footage in construction. The new area can then be framed 2x6 or whatever you like.

The problem isn't the space, but the other work involved. Our deck would need to be rebuilt sonner than we are ready too. We also have an outbuilding that would be in the way and would need to be moved. Going up would be the cheaper option.

 

[Sparky617]

When our neighbors went out they were able to continue living in the house with minimal interference from the construction. I'd agree going up you'd need to move out for the duration of the project. At a minimum until it is weather tight and regardless it is pretty messy. Just doing my basement has been a bit of a mess in the house and I can close the door to segregate the basement from the first floor. If I don't kick off my shoes when I get to the top of the stairs I'm leaving drywall dust foot prints.

 

[swimmer_spe]

When our neighbors went out they were able to continue living in the house with minimal interference from the construction. I'd agree going up you'd need to move out for the duration of the project. At a minimum until it is weather tight and regardless it is pretty messy. Just doing my basement has been a bit of a mess in the house and I can close the door to segregate the basement from the first floor. If I don't kick off my shoes when I get to the top of the stairs I'm leaving drywall dust foot prints.

The plan is to use our camping trailer while the addition is happening.

 

[Sparky617]

The plan is to use our camping trailer while the addition is happening.

As long as you're prepared for being out of the house for the duration. My parents renovated a 1900's house while living in it after they retired. I'm surprised their marriage made it through the experience.

 

[bud16415]

My first house a 1880s farmhouse I remodeled 100% and I paid a months extra rent where we were living to get started. I did more work in the one month when we were not moved in than the next year moving stuff around the project at hand. I laid 500 sq foot of floor in 3 rooms without taking the furniture out. The tricky one was I laid it under a baby grand piano without moving the piano.



So yes you can do just about anything.



Just about the time in your life when you make enough room then the kids leave and you start working to downsize.

 

[Sparky617]

Are you contracting this out or DIYing it? I've been DIY finishing my basement for the last year plus. I'm finishing the drywall now. I have to tile the shower, final paint on half, all paint on half, install the toilet and vanity, doors and trim. Working full time at my day job I put in 4-5 hours most weekends. I can close the door and walk away from it with no real impact on the house. If you're DIYing this you really need to take some time off from work to get it under roof and dried in. A couple of days isn't enough. You'll quickly tire of spending EVERY available moment working at your second job.

 

[bud16415]

I once planned an addition and had several contractors out to quote it and asked for quotes two different ways one being 100% finished and the other being just closed to the weather and finished on the outside only where I could then take my time and do plumbing, electrical, insulation, walls and trim. At that time no one had any issues doing that and it brought the cost for getting the project started way down and more importantly the time the house would be opened up.

 

[Sparky617]

I once planned an addition and had several contractors out to quote it and asked for quotes two different ways one being 100% finished and the other being just closed to the weather and finished on the outside only where I could then take my time and do plumbing, electrical, insulation, walls and trim. At that time no one had any issues doing that and it brought the cost for getting the project started way down and more importantly the time the house would be opened up.

Very viable option, might be tough to finance conventionally though. If you're doing all the work out of pocket or maybe with a HELOC with plenty of equity in the home not a problem. With a construction loan it might be a problem.

 

[swimmer_spe]

Are you contracting this out or DIYing it? I've been DIY finishing my basement for the last year plus. I'm finishing the drywall now. I have to tile the shower, final paint on half, all paint on half, install the toilet and vanity, doors and trim. Working full time at my day job I put in 4-5 hours most weekends. I can close the door and walk away from it with no real impact on the house. If you're DIYing this you really need to take some time off from work to get it under roof and dried in. A couple of days isn't enough. You'll quickly tire of spending EVERY available moment working at your second job.

It will be contracted out. I do not have the skills to do something that challenging.

Very viable option, might be tough to finance conventionally though. If you're doing all the work out of pocket or maybe with a HELOC with plenty of equity in the home not a problem. With a construction loan it might be a problem.

We will be doing it with the proceeds from the sale of property. So, not much of it will be financed, if any.