RadonSeal or Drylok, or both?


Old 04-15-05, 08:27 PM
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RadonSeal or Drylok, or both?

I have old cinder block for my basement wall. No huge water problems, but it does get damp to the touch. I've read in the forum about Drylok, but what about a product called RadonSeal, which is supposed to penetrate the concrete and seal it. For radon, yes, but they also say it keeps out water. Has anyone had any experience with it? Would it be OK to first do RadonSeal, and then paint on Drylok? Thanks.
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Old 04-19-05, 06:34 AM
Join Date: Jan 2005
Location: North Virginia
Posts: 192
I have been wondering the same thing for awhile. I am still stuck doing research on it because of a $1600 transmission repair bill for my wife's car.

From what I have gathered, Radonseal claims to be better at sealing then DryLok. Radonseal is a silicate based sealer and just about every commerical construction job requiring a concrete sealer specifies that only a silicate based product. The company that makes Radonseal (Novion) is a member of the BBB and they are in good standing. I have searched and searched the internet and have not found any complaints against the product. I saw one internet post (with no sources) that said the EPA says the radon sealing ability of these types of products is not permanent and only last for a period of years (but I haven't found the original source for this).

They seem to have a good product and appear to stand behind it, but I have never used it nor have never been able to find anyone that has ever used it. There are a large number of companies that make similar products out there, just search for silicate concrete sealer on the web.
Old 04-19-05, 08:03 AM
Join Date: Mar 2005
Location: USA
Posts: 6,130
RadonSeal or Drylok, or both?

I am not familiar with RadonSeal, but it appears to be more of a temporary coating on the surface. Silicone sprays used on masonry walls have a life of 3 to 5 years. During that period some brands recommend that you do not put another coating over them for that period. If they really work, nothing should stick to them.

More permanent waterproofers for concrete will bond with and/or become a part of the concrete itself. On old-time product that is very basic and has been around for a long time is Thoroseal. It is part of a well known product line including ThoroPlug and others that have been used very sucessfully.

ThoroSeal is conservatively shown a "damproofer" without any of the exagerated claims. I used it to help solve a water problem in my basement. After applying it and before I realized how much water I had, I looked down in the cores and saw nothing but water. I punched a hole 3 feet up from the floor and the water squirted about 15 feet across the basement. I immediately punched a hole at the base to relieve the pressure. That is water proofing!!!!

To preserve my foundation, I ultimately put in a interior drain tile system for structural purposes, not for waterproofing since that problem was solved by the Thoroseal. This illustrates that there are a number of good, economical basic products that do work for permanent solutions.

Applying Thoroseal is like slopping on thin pancake batter with brush on a wet wall. You can get fussy about the floor, but I just spread it out and it painted it with my floor paint later. It lasted for 25 years at last report.

Good luck!

Old 05-20-08, 03:19 PM
Join Date: May 2008
Posts: 1
drylok vs radonseal

drylok is a paint on waterproofer that you will need to paint on the walls to keep the water from penetrating a porous brick and block. the radonseal is for crack repair IE in basement walls. this is my experience for now as i am still searching the pros and cons of radon seal opposed to spending $1600 on someone digging from the outside to repair a crack in my basement wall.
Old 06-02-08, 11:54 PM
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Join Date: Jun 2008
Location: Near Washington DC
Posts: 6
Behr Concrete & Masonry waterproofing versus Drylock

Before you do any waterproofing, you might think about getting a contractor or inspector to check if there are any structural issues related to the dampness. My house is 38 years old and the cinder blocks have definitely lost the battle against the acidic soil and the wet weather of Washington DC. Drains & sump pumps cost me over $20K, so I learned the hard way, it's better to know the worst sooner rather than later.

The Behr Concrete & Masonry waterproofing is a relatively new product that is supposed to do the same job as DryLok. I have used both and the Behr (#857 for Masonry & Concrete - not the one for Exterior Brick and concrete block) is much much easier to use. You can use a roller with a 1" nap and a little pressure and it seals up the little holes in the concrete like a charm. Of course, you'll have already prepped it by wire brushing (beats Myriatic acid (sp?) any time) and filling in obviously holes & gouges that may exist.

Hope this is helpful. Enjoy.
Old 07-15-10, 01:12 PM
Join Date: Jul 2010
Location: USA
Posts: 4

Funny I should find this thread. I went through this a couple years ago. My mistake was using Dryloc in the first place; a waste of time in my opinion. I ended up removing it because the seepage returned the following summer. (12 year old concrete block wall). I tried calling for a refund and they refused because efflorescence (sp?) was showing up and if you have that stuff the warranty is void.

I ended up using RadonSeal Plus ... the stuff mentioned above a few times. I was actually surprised how well it worked for me. It is not a surface coating, contrary to what "Concretemasonry" has said. It penetrates deep and reacts inside the block. I'd never use a surface sealer again because they just push right off when exposed to negative pressure. I called the company and asked about painting over it and they said not problem. I know have a dry, off-white wall in my basement
Old 08-14-10, 09:33 AM
Join Date: Aug 2010
Location: USA
Posts: 1
I've been doing some searches about the simular problem I have. There are 2 corners in my basement that are experiencing a slight problem with water. One of the walls does get damp to the touch sometimes, & the other corner isn't as bad. But when I pulled back the carpeting in that corner I noticed a small wet area. Currently the concrete walls are just painted, & I assume it was with just a normal wall paint.

My plan is to finish the basement building a frame for the finishing panels. I will need to take care of the water problem before I cover everything up.

I've been looking around at a few products UGL, Zinsser, & Radonseal for the wall waterproofing paints. Everyone says their product needs to go onto a bare wall to work properly.

So I've looked at using a paint stripper to get the paint off of the walls. Then once the paint is off, then I thought it would be a good idea to use one of the penetrating concrete sealers before I apply the waterproofing paint.

I'm hoping that this will give me a double layer of protection before I cover everything up, & then can't get to the concrete walls again.

I start doing some searches on ThoroSeal to see what I can find.

But I was interested in getting some thoughts on my plan, & finding out if this is a good idea, or if there is a better way.

ThanksBeer 4U2
Old 08-18-10, 05:22 AM
Join Date: Feb 2010
Location: usa
Posts: 236
38yrs i've been doing this work & haven't found anything to stop water from penetrating foundation walls yet other than a properly applied/installed waterproofing system,,, believe me, if there were something, we'd use it. has anyone thought about this - IF you could stop the water from showing up on your very fine bsmt wall, exactly WHERE is it being stopped ? ? ? of course, INSIDE the wall - so we haven't stopped anything - just hidden it from view.

current bldg code calls for a .003 dampproof coating on ext below-grade bsmt walls,,, not only ridiculous but totally inadequate,,, until bsmt walls're waterproofed, we'll still be in business & make a good living Beer 4U2

have no experience w/'radon-seal' products but radon's a gas, not a liquid,,, for radon, we usually install bsmt air exchangers as the other method's a french drain type system w/exhaust fan.

[personally, i see no difference 'tween thoroseal ( a product i do use ) & 'drylock' applied to interior walls]

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