Crawl space or a slab?

From personal experience I prefer a crawlspace. We had one house built on a slab and we had little rolley polley type (dead) insects found along the outside walls when cleaning. Also, building on a slab will require you to run ductwork above if you were going to have a forced air heating and air system. As we all know heat rises and I don’t believe you would get the maximum effect from the heat. Now, on the other hand, if you live in a climate where air conditioning is not as important you could run a in slab heating system to radiate heat upward. I understand these to be very nice and effcient.

Just my 2 cents.

Roger

-- Fast is good, but accuracy is everything. Wyatt Earp

I would go with a crawlspace with alot of access under it. don’t do a crawl space and you really have to crawl if you want to do some additional working give yourself 3 or 4 feet. It is alot easlier to move around and do all the extra that you forgot when you orginally built it or your wife wants something moved. trust me.

I live in the south, and air conditioning is important.

-- CJIII

Hey woodworker – not that I’m an expert, and I live in the cold north, but slabs are difficult to work with. My son lives in MO and his house is on a slab. Major problems when it comes to reworking plumbing (if you get a better idea 5-years down the road). Not having to worry about cold weather, a crawl space would really help. And as hardwood mentioned – gives you a lot of space to store things that you don’t use all that often.

Good luck!

-- No matter how many times I measure, I always forget the dimensions before I cut.

I prefer crawlspace myself…for all the reasons mentioned already, plus I find much it easier on the knees and feet when walking around on wood that flexes, rather than hard cement.

My brother added an apartment for my parents which he built on a slab. The guy he had plumb the slab did a poor job. The sewer pipe cracked causing my folks to get very sick. It took them a while to figure out the problem, but my brother finally ended up jackhammering the living room floor and, well you can guess the rest. Put my vote down for “crawlspace.”

i think a slab under the carports, wrokshop, and porch. even though there slabs think about drainage the warmth provided by elevating the living areas is imeasurable yet mostly energy conserving if it is a slab the floor temperature in my apt which is on a slab is constant 52 cold in winter yet cool in summer. i live in pacific north west. at about 300’ and i rent. i think i would go with a crawl space. slabs are i think a whole lot less expensive. plumbing can go in the walls and the slabs can be segmented i would think a slab plumbing job done well would be more secure in a shifting environment but with plastic tubing there kinda flexable somthing i too am looking into. i am partial to one floor buildings and like the slab idea best. no stairs and no creaky floors. yet this adds character to a home. so it s your call if you want you can put down a slab and raise the floor for temperature and plumbing this is a noisy compromise i know you would need to sound dampen the plumbing or listen to it could be neat. rugs work. with a hard foam insulation. or rubber mats. crawl spaces sometimes need pestasides. slabs don’t.

-- joseph

Being that you are in a Southern State, slab foundations are, at times, acceptable solutions. However, I have never encountered anyone who opted for a slab foundation that were satisfied with their choice. I have family members who live in Florida and Georgia. I’m not sure of how the foundation was constructed for my Georgia relatives, but I do know that My Floridian (Pensacola) relatives have had their slab-foundation home since (at least) the early 70’s – and they absolutely hate the fact that they went the route of the slab.

Being that I live on the Northern Tip of the Application Mountains at an elevation of about 2600 ft., building a slab foundation for a home is almost non-existent, and in most cases, homes have full basement foundations (the top of the footer must be at least 3 feet below surface level due to the frost-line).

Without knowing your particular lot terrain, soil conditions, and flooding conditions for your area, I would feel comfortable in saying that, unless you absolutely were required to have a slab foundation, A crawlspace foundation would be the preferable of the two. However, I would even take it a step further and recommend that, if possible, you choose a “mini-basement” type foundation. When I refer to the term “mini,” I’m basically suggesting that the foundation have all of the properties of a “full” basement, with the exception that the headroom would be either half, or even less than half, of they typical full basement headroom, and the crawlspace would be accessible from the exterior or the home (rather than from an interior stairway leading to the crawlspace).

The foundation would consist of a typical poured and keyed footer (again, local ordinances and/or lot conditions may require the footers be to an acceptable specification). That would be the base for either a typical CMU (masonry block) wall, or a rebar-reinforced formed-and-poured vertical wall. However, as some choose to just pour a bed of gravel or whatever aggregate is regionally applicable, I would take it a step further & have a a slab poured within the CMU/Poured foundation walls, as well as have the slab pitched towards an installed drainage system.

I know that it may leave you to wonder, “why don’t I just go with a full basement foundation?” One of the downfalls of having a crawlspace foundation is, should you have a situation in which flooding occurs, or even if a failure in the plumbing system could cause the crawlspace to be flooded, you would most likely end up with having a problem with mold. By having a drainage system in place as I described, you would advert a potentially hazardous situation which is almost to be expected as a certainty during the home’s lifetime.

With all of this being said, your local building codes trumps any and all of what I have mentioned. But, if you have the choice, I would defer to the option that I mentioned. My last house had to be built with a crawlspace foundation (the lot consisted of about 1-1/2’ of top soil, and below that was nothing but highly compacted clay and/or solid rock, so blasting a 9-foot hole in the ground was not an option), and I insisted that the foundation was built as I mentioned above. In the 7 years in which I lived there, we had 1 occasion involving heavy rain, and 2 occasion which involved rapid snow-melts, that caused water to infiltrate the crawlspace.

....and many apologies for the “wordy” response.

-- John Vrobel - JV Designs