White cement on a roof?

beeza

Silver
Nov 2, 2006
3,165
267
83
A question for the building experts.

My house has a Bermuda style roof that needs painting....again!

The paint doesn't last long, maybe two years at most. Last time I painted it, I had an army of people with scrapers, removing all the old paint. A painstaking and messy job. We then painted it with a latex based roof paint, but it's already peeling, bubbling and allowing filtration again.

So my question is borne from my recent swimming pool refurbishment. My pool is coated with Diamond bright, which is mainly just white Portland cement with coloured stone particles embedded into it. It's supposed to be hard, water and chemical resistant and last forever.

So I thought about applying a thin layer of white portland cement on my roof rather than painting it again. Hopefully it should last longer than the paint and certainly not bubble up and peel, which is what causes the porousness.

Any thoughts?
 

ju10prd

On Vacation!
Nov 19, 2014
4,210
0
36
Accountkiller
I would suggest that you use an elastomeric roof paint rather than acrylic.

Sherwin Williams do a very good roof elastomeric paint and their products are available in DR.

Preparation is key. Perfectly clean, dry, no fungus.

White cement does not solve the problem. Cement is porous without waterproofing additives and again a clean key to the existing substrate is essential.
 

AlterEgo

Administrator
Staff member
Jan 9, 2009
20,151
1,531
113
South Coast
Last month we put on a Lanco sealing paint, it lasts quite awhile. Not cheap, was about 7-8,000 pesos each 5 gallons [I think we needed 15 gallons for our roof, it's thick], but it works.
 

donP

Newbie
Dec 14, 2008
6,942
174
0
Last month we put on a Lanco sealing paint, it lasts quite awhile. Not cheap, was about 7-8,000 pesos each 5 gallons [I think we needed 15 gallons for our roof, it's thick], but it works.

We also used Lanco once. I think it said hecho en Puerto Rico.
It was expensive bad stuff.

donP
 

AlterEgo

Administrator
Staff member
Jan 9, 2009
20,151
1,531
113
South Coast
Lanco Elastomeric Seal Coat?

That sounds right. They had two kinds, one was much cheaper, about 4500 pesos for 5 gallons.

donP, it has worked for us for years. Our roof isn't entirely flat though, it has a small peak and pitch, might make a difference?
 
Aug 6, 2006
8,751
2
38
First you blast off any flaking with a pressure washer. Then you swab it down with a 20% solution of Chlorox (any brand that has the same formula and concentration) then after that is dry, you apply elastomeric paint.
It should last for five t=years, though you might have to swab it with Chlorox and steregent to remove mildew (black stuff).
 

zoomzx11

Gold
Jan 21, 2006
7,848
429
83
I have to repaint my house often, too often. First to go black with mildew is the roof. Next paint job I am going with go with extreme prep and I am having laborers doing it not the painters as they charge too much and do not do a good job. First off scraping then washing with trisodium phospate then finally chlor and a check to see that all chalky surfaces are clean and fresh water rinse. Next I am buying an anti mildew additative for the paint. You can buy paint that says its anti mildew but I am a skeptical person. I am convinced that the extreme mildew here comes right through the paint. I have never lived anywhere with mildew like the DR. Even my shoes get it in the closet if I am not careful. Its just a theory but I will let you know if it works. Paint jobs done right last for years and years in other places, why not here? We shall see. I did do a test on a section of the roof that went bad. I used a chlorine solution and voila, it was mildew that killed the paint. I am thinking that Dominican mildew is just tougher than normal mildew.
 

dv8

Gold
Sep 27, 2006
31,270
359
0
we use urethanizer, also from lanco. our roof is sloped. the building is 20 years old or thereabouts. zero leaks of any kind. we repaint about every two years. the house is close to the ocean so considerable exposure to salt as well as general humidity and heat.
Lanco :: Urethanizer
 

beeza

Silver
Nov 2, 2006
3,165
267
83
So if I repaint, does it seems likely that I would only get around five years out of it before having to do it again?

It seems like the direct sun is the cause of the paint bubbling and peeling.

Isn't there a more permanent, but cheaper alternative than laying tiles?
 

ju10prd

On Vacation!
Nov 19, 2014
4,210
0
36
Accountkiller
So if I repaint, does it seems likely that I would only get around five years out of it before having to do it again?

It seems like the direct sun is the cause of the paint bubbling and peeling.

Isn't there a more permanent, but cheaper alternative than laying tiles?

The product Hydrostop Premium Coat link below is extremely effective and if installed by an authorized installer comes with a long guarantee. It is also an elastomeric roller applied product and is reinforced with fiberglass mesh. Elastomeric paints have a degree of flexibility which allow for the thermal movement you get between direct sunlight daytime and clear cooler nights. The bubbling you mention is down to poor substrate preparation and the paint de-bonding.

PremiumCoat System by HydroStop


I've used it on several projects successfully throughout the Caribbean and is very cost effective and I know it is available in Puerto Rico.

You could ring Quest and see if they have an authorized agent/installer in DR.

Oh...should mention....tiles fly in a hurricane! Hydrostop comes with Miami Dade certification.