Sorry bro for late response but I was also waiting for others to respond. Anyway I find DRYLOCK a very reliable concrete sealant, for bare hollow blocks, plastered concrete walls or fine finished surface. Only thing is that its very expensive, one can would cost a little less than 2K. Its easy to apply on rough walls, for first coating, use a stiff brush pressing the sealant to the surface crevices, cracks and small holes and then let dry for a day then for the final coat use a roller for easy and even finish application. Before the sealant application, wire brush mo muna ang wall surface to remove loose particles and other dirts sticking on the surface. I used it inside my tool room two years ago and really very effective.

Another brand I like is the PR1MERO water based Multi-Sealant, very effective as well and much much cheaper than the Drylock. Same procedure of applications, but only by using a brush and can be re-coated after an hour. Comes in different colors too.

Hope this helps !!

Sir Rosy, thanks for the insights about Drylok and Pr1Mero....I think I will try the Primero first for testing since it is less costly as compared with DRYLOK . Practice, practice to learn new things. Salamat po muli.

If you will try the Pr1mero brand, you can do experimentation by just buying 1 or 2 canisters first, its 600g per canister and will only cost you Ph 249.50 each. I think you will like it as well.

Good Luck !!

Used drylock in our cement water tank about 10 feet high rough finish... So far no leak 3 years now.
Drylock go deep inside your concrete wall, so i think its effective.

By the way sir, in case i will use PR1MERO or DryLok on a painted wall surface, do I have to strip off the old paint OR can I just paint over it?
Maraming salamat po Mr. Rosy and Mr. Nick.

Stripping the old paint off is the best way to do it. If you don't you are ate the mercy of the bond strength between the old paint and the concrete.

Baka matatanggal na pala yung lumang paint, sayang lang pagod at gastos mo.

@ bonruiz,

According to the flyers/manuals of the two brands mentioned, it is best that this waterproofing sealant be applied direct to the bare finished or rough concrete wall surface so that it will bind and penetrate deep inside the wall . As bro joey said, it is best to strip the old paint of the surface to make it 100% effective. Useless if there is some sort of a film or barrier between the sealant and the concrete surface, masasayang lang ang waterproofing sealant plus gastos.

Thank you very much for the helpful advice. Have a great day!

Stripping the old paint off is the best way to do it. If you don't you are ate the mercy of the bond strength between the old paint and the concrete.

Baka matatanggal na pala yung lumang paint, sayang lang pagod at gastos mo.

Thank you very much. May I know the best way to strip the old elastomeric paint? Since scraping it is very hard. Maraming salamat po.

Simply buy a bottle or two of paint stripper from your neighborhood hardware store and then apply the solution
on the painted area by brush, then wait a few minutes, then you can scrape the paint very easily.

Hope this helps ! 😉