What's the best way to raise up an exterior concrete porch to enclose it and convert it to interior space?

Question

The porch was poured the same time as the interior concrete two years ago and has no cracks but does not have a vapor barrier as the inside does. The porch has the same footing as the rest of the house. I was going to use concrete adhesive between the old and new concrete but if I have to add a visqueen barrier, it seems like the adhesive won't do anything.

Answer 1

If there's room for a crawl space under the new floor level, I would put a couple courses of concrete block on top of the concrete porch pad perimeter. Use a solid cap block and metal termite barrier with a pressure treated wood sill plate before building the 2X4 or 2X6 inch stud walls. Make sure to check for the proper way to ventilate the crawl space and run the wiring, HVAC and plumbing before laying down the floor decking since it will be difficult to work in the crawl space under the floor.

Answer 2

I would NOT try putting plastic between the courses of concete at this point. You don't say how much higher you want the concrete for your living area, so there could be other possible fixes for this if we knew more.
You should roughen an area around the perimeter of the existing concrete at least 6 inches wide (more is better). Apply the bonding agent per manufacturer's instructions and place concrete. You may wish to add some wire mesh to the pour for additional strength in your slab (if the thickness of this addition is around 6" or more). Make sure you cover with plastic for curing after you finish the concrete, or use a curing compound.

Answer 3

There is another way to tackle this if your not going up more than a few inches. It is a common way basements are done. Figure out your rise of the floor. Then minus 2 inches. Take the remaining amount the go to your local home center and get that sheet insulation in the thickness you want. Its usually made out of the white Styrofoam. Lay it down on the floor, seal the seams with the low expanding foam in the cans it will act as a glue and make it one seamless vapor barrier. Tape all the seams with house wrap tape. Then place down two layers of tounge and grove sub floor and screw it down with tapcon screws. Its a cheap and easy way and you will have a nice amount of insulation.

Answer 4

It may be wiser to use a vapor barrier on concrete, then build up to proper level using wood sleepers just like joists.. Then a layer of OSB or other wood product. The space below floor can be insulated. Floor would be quiter, warmer. & it is always good to check also check code per previous answer.

Answer 5

Not sure how much you need to raise it I am guessing inches rather than feet. I agree with the answers who say do it in wood
I would rip treated wood almost like making a deck on the top of the slab. It Would be warmer and allows for easier transition between floors. could be alot cheaper too depending on how much concrete you need.

Answer 6

First I would check with the local building codes office and see what they say about everything. You might have to produce a set of your plans or what your intentions are. Then you might ask them questions for your area IE: frost depth, etc. go from there.