Home inspection findings by Frank Schulte-Ladbeck, Professional Real Estate Inspector TREC# 9073

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Can I Turn My Porch into a Room?

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We all want more space. Garages are turned into rooms. Porches are also converted into rooms. However, this may not be a wise idea.

My wife wanted a roof over our porch last year.After the job was done, she claimed what a wise investment this would be, because we could eventually turn this space into a room. An outdoor room, I responded. You see, I did have plans that we should add a room in that space. No, she argued, we can convert this into a room by adding walls. She was quite adamant in defending her position. Why was she so convinced? Because the remodeler told her that this was all we had to do. I reminded her that I am a home inspector, and that I do know something about building. We would have to take down the structure that was erected for the roof if we wanted a room, and this seemed a waste to her if we were going to build the room. The evidence piled up against her belief, but she did hold onto it. I finally found some proof that will put the nail in this notion.
    Why can we not build a room on a porch? You have to understand foundations. A foundation is designed to hold the weight of the structure resting on that surface. The foundation also has to deal with being lifted by frost in the ground, so we make it deeper than the depth the frost reaches in our area, the frost line. In Houston, we go deeper with our foundations than needed, because we base the frost line for the state on temperatures in the panhandle. All of this means that the foundations are deep. Areas that do not need to support the home do not require such depths. To save money by using less cement, builders will make these cement slabs shallow in depth. Garages do not have the deep foundations along the entrance edge, since the house is notsupported there. The driveways have a shallow depth too. Then we come to porches. Porches which are attached to the house may have a proper home foundation along the edges that touch the home, but most porches are separate slabs, which are about as deep as the driveway. These can be different depths, but I see these averaging about a foot deep at most. With frost and the weight, these cement slabs crack. In fact many porches crack without this weight. Frost and moisture in the ground will raise these slabs unevenly, causing cracks.
    Iimagine that my wife’s plans fall into the course homeowners do take. You set a table on the porch to eat outdoors. I even built a sideboard, added side tables, and a carpet. We built the roof to make this space feel more like a room. The insects bother you, so you enclose the space with screening. Finally, you want more use of this burgeoning room, so you take the final steps of adding walls, air ducts, and wiring. When you first put everything up, the room looks good, and you notice no problems. Shortly, you will notice the cracks, starting in the floor. Then you may realize your mistake.
home additiontile cracks
    I cannot always determine exactly the cause of every problem in a home inspection, but experience and clues hint to the culprit. This was the evidence to present to my wife if she had thoughts of adding walls to our porch. In the photo, you can see that there are large cracks in the tile and slab. To enter this room you have to step down from a door that was originally the back door. On the exterior, we see that the cement slab has been tiled. This is common in Latin America. What struck me was how low this foundation was. Home additions are often not on foundations which are attached properly to the old foundation. In fact, they are often lower and on a separate foundation. That might have been the case here, yet they are a bit higher than what I was seeing. The next clue came from experience, which was confirmed when I was up on the roof. Builders add porches outside of the door in backyards in homes built after 1950  from my experience. This is not always the case, but the other homes that I could see from the roof had this porch. The last bit of evidence was the nature of the cracks. They fit with what I would expect when weight was applied to the slab of a porch. Maybe more cement was added to the porch slab. I think that is a possibility with this room.
    Can you use the porch for a room? There is a chance that your porch may have sections that are part of the home’s foundation. In the case of the home in the photos, could we build on a porch slab that is not a proper foundation? You can dig down to create the correct foundation depth along the edges, and then a new slab could be poured over the old porch slab. This will save on some cement if you are looking to cut costs, but you need those deep edges to support the weight.

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6 Responses to “Can I Turn My Porch into a Room?”

  1. Mey Says:

    So, did your wife ever get her added room? I’m curious if it is at all possible to be done when taking the proper route and not cutting corners. I own what I believe to be a 1950s-60s Ranch house between Austin and San Antonio. It truly is a beautiful home in an older neighborhood where younger couples and families in their late 20s to 30s are moving in and fixing them up. I love being outside on the porch, but I feel like I just don’t get any use out of it and I’m wanting to convert it into a tv room/ small office. I’m glad I found your blog because I had the same thought process as your wife did.


  2. I have been in your area quite a bit lately, and I have seen some wonderful porches with great views. No, my wife has not managed to turn it into a room yet. I have been building outdoor furniture for a few rooms: the porch in the backyard; the porch in the front yard; and an outdoor kitchen area; so she is happy enough. She is bothered by some birds over the back porch though. Good luck with your plans. I hope that you will have some good views from the planned sunroom/office.


  3. Lois March Says:

    I am having thoughts like your wife. With the heat, we have had, the past 3 years, I am not using the porch like I used to. Also since my pool was damaged in a major storm, a couple of years ago, I had to take it down so now the grandkids don’t come like they used to. I would like to use the space for a great sewing/quilting room. Mine is built like a deck ,20′x18′, but 4″x4″ posts (in concrete)were brought up and a hip roof added to join the house. The floor is level with the house. I know it would need a foundation under it but have no idea what kind of costs it would be. I would not put windows all the way around but enough to give light. I know I would need to insulate and add some sort of heat/air. Of course, drywall,and a door going out. Am I talking 10,000 or $40,000?


  4. Hello Lois,
    It might be safe to say that you are looking at a figure between the two. What you will need is a structural engineer. He will evaluate the foundation needs, and draw up plans for the contractor. These plans could then be submitted for the building permit. Considering that the deck is already handling the weight of a hip roof, the additional piers would have to handle the weight of the wall framing and material, insulation, windows, doors, duct work for air conditioning, and electrical work with fixtures. This means that you can have a pier and beam foundation for this room, so you may only need a few extra piers; some reinforcement for the beams may be needed. If trying to go with a slab foundation, we can be discussing more money. In that case, the existing supports would be removed as the slab is poured.

    The structural engineer can give you the best cost analysis of the project, since he will know what needs to be done. In the long run, his service would save you money.


  5. Sam Says:

    Thanks for posting this. it rectifies my reservations on a enclosed porch that was built without permit on my 1960 Nebraska house. I should have torn the thing off when i moved in. Naive me has put $ into the roof, $/time into reinforcing the framing, etc over the last 7-8 years. I want to rip out rotten the wood floor this year & put a concrete slab down. Just strongly desire a stable floor,get rid of the wild animals that hide there, more clearance to the ceiling so I can put in an outdoor fan & maybe move the washer/dryer & dog kennel out there – no desire to enlarge the living space. I have not found any footings on it. I dunno if I should dig a trench in 2-3 foot sections and make a foundation that way… ug! Your article has helped me at least know that what the contractors have told me over the years is hooey. I don’t like fixing anything more then once :)


  6. Thank you!


© Frank Schulte-Ladbeck Professional Home Inspector Houston, Texas
Frank Theodor Schulte-Ladbeck
home inspector, TREC# 9073
Houston , Texas , 77063 United States
713.781.6090

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