Concrete sealer?

[G Mulcaster]

Hi Group,

I have a concrete entrance to my home, on the windward side. During heavy rains, the concrete seems to absorb water, the water transfers through the concrete, and the inside of the house gets wet.

What would be a good sealant to use on the outside?

Thanks, Gary Please remove XXX in email address if email reply is desired.

[Joseph Meehan]

It does not sound like the water in coming in through the concrete. I would look for other sources.

We will need to know more about the construction details. How is the concrete sloped (towards or away from the house) Does wind make a difference? What kind of siding and age. How is your roof? Exactly where do you see this moisture. Is you home on a slab or do you have a basement. Etc.

[mark Ransley]

Water doesnt go through concrete, only cracks in mortar - tuckpointing , or areas of failing caulk.

[G Mulcaster]

Thanks for responding.

Roof is good, siding is good to the extent known from visual inspection.

The area in question is a slab on grade. Originally a carport, it was converted to a rec room. A 9" high cement foundation was poured on the slab to support the walls. No problem there.

The entrance door was placed on the slab with no foundation. During wind driven rains, water worked its way under the door into the rec room, despite use of expensive Geocel sealant.

My solution was to tear the entrance apart, build a 4" high concrete foundation (but only 4" wide to fit the door), and install a new door. Concrete was then poured to create a 1" in 4' slope away from the entrance.

Now, after a strong wind driven rain, water shows up where the inside slab meets the bottom of my 4" foundation.

I suspect the problem is lack of a proper seal between the concrete surfaces. That is, between the old slab and new foundation and between the new foundation and the new sloped entrance.

So, I think I need some sort of brush or spray on clear sealant to apply to the outside of the entrance. I have Thompson's Water Seal, but would prefer something more robust.

Thanks, Gary

Please remove XXX in email address if email reply is desired.

[Tom Baker]

I think you have a condition similar to water penetration through a brick wall as noted in other posts. As you suggest, the water seems to be seeping along the joint between old and new concrete.

The best solution would be a water stop added during the adding of concrete. Various rubber shapes are marketed for this, but one could be made. The existing slab would have been cut and the stop placed to bridge the joint.

At this point, sealent placed along the joint might work.

TB

[Roger]

I agree it may be coming thru the base of the new foundation along a fine crack there.. You might also consider a concrete colored polyurethane caulk or other durable caulk pushed in along all exterior seams. If none of this works, I would consider putting some kind of doorway cover or awning like device that would keep all but horizontal driven rains off the door and the entry area. This could be your only long term solution.

[Tom Baker]

Door way protection and drip caps often help. Here on South Carolina coast, rain is often driven along an extierior deck and below doors. The 4 inch combing in this project would have solved the problem, if it weren't for the seam.

TB