Painting new block construction

[jefff]

Hi,

I am having a garage built that will be unfinished block on the inside and painted stucco on the outside.

My question is: how soon after the block goes up can I paint the inside? I know *how* to paint it but was unclear on how long the block should set before being painted.

This is in central FL so the temps shouldn't be too cold and the humidity is pretty low for the next few weeks.

My goal is to paint inside as soon as I can before the final electric work is done. That way I don't have to work around surface mounted conduit and boxes.

Thanks for any advice...

JF

 

[Jinks]

By the time it's roofed you can paint it. The block is dry, only the mortar has any moisture & that will be dry by the time the roof & doors are on. On the outside it's a good idea to give the stucco plenty of time to dry before painting. Your stucco guy can tell you how long.

 

[Half-fast eddie]

Your stucco guy can tell you how long.

When he says its ok to paint the stucco, it’s ok to paint the inside.

 

[jefff]

By the time it's roofed you can paint it. The block is dry, only the mortar has any moisture & that will be dry by the time the roof & doors are on. On the outside it's a good idea to give the stucco plenty of time to dry before painting. Your stucco guy can tell you how long.

Thanks. That's about what I figured. I'm not worried about the exterior.

I just wanted to get the interior painted before any of the finish work. Sounds like I can time it pretty well. I'd only need a day - maybe two to get it primed and painted.

I just didn't want to rush it and trap any moisture. But yes, since it's just the mortar joints it should dry fairly quickly I'd guess.

 

[Firebrick43]

What said above is only partially true.

Any masonry system needs to set 60 days before painting or the alkalinity and efflorescencewill damage most paints.

However there are sealers/masonry prep products that allow 7 days. I personally use zinsser lock down which is a watery thin product that goes really far and you can use standard paints over the top.

Many block filler paints are also formulated to go on sooner and resist the alkalinity.

 

[strutaeng]

Look at the paint/primer system Technical Data Sheets you are using.

I did an addition and used CMU as veneer on the outside. I used a PPG special block filler primer/surfacer and it said 28 days IIRC. I spent time removing small little mortar spatter, scrubbed with a stiff brush and hosed it down. This was in the summer so it went fast. Turned out nice.

Make sure you back roll to get the primer into the pores. Use topcoat of choice.

 

[nadogail]

I agree with the suggestions of others.

 

[Zeke]

Grouted cells will stay wet for a lot longer than empty ones.

 

[Studebaker Shop]

From my experience if you have a space heater that can warm and dry the interior area of the garage...(24 hours), do that first. Then, take a stiff brush/push broom and go over all the interior walls to knock of any loose materials. After the garage is cleaned out and as dust free as possible...us a paint intended for masonry. I have used "Kils" it works well. I also suggest spraying it on as opposed to rolling the paint, (better coverage). Then with the space heater on, let it dry a good 24 hours. This method has worked for me. Good luck! David
Note: other masonry paints I have used were Dry-Loc paint sealant and Thor water seal paint. they may have been regional brands available where we were living at the time.

 

[Half-fast eddie]

Space heater … you talking about a kerosene fired salamander? Bad way to heat & dry out the space, it gives off a lot of moisture

 

[Studebaker Shop]

The two times I sealed or painted an interior of a block wall garage I used my LP gas heater for my prep. Yes, I know walls can sweat but if you dry them with a room temp value 68 to 70 over a full day or 2 the interior walls will dry enough for the paint or sealant to adhere much better. Brushing the walls of loose residue is also important in the prep work.
The salamander heaters tend to burn very hot and are directional, they are also odorous. If you use one you have to reposition it often and vent the area more so than with LPG. We used Salamander heaters in the military and although they offer fast heat. they are not the same or as a good LPG space heater for a safe and consistant warming. We started using LPG heaters mounted on trailers with 4 or more burner heads that could be adjusted for temp and direction. One 6 head LGP trailer in a 40'x100' concrete and block bunker would heat it up for working comfort in about 1 hour. (In upstate NY during the winter months. )
When we did use salamander type heaters in large hangers, bunkers and/or Quonsets, we could actually produce condensation or wet spots in the hanger. however the LPG heaters burned more evenly and heated and dried the same areas in about the same time with out the condensation. Also no head ache reactions to the kerosine odor and far less time spent refueling.
This is the reason I went to using my own portable LPG heater...and yes LPG heaters do need proper ventilation to operate safely. I heat my 14'x30' stick frame garage in CT winter months with a 1 head LPG heater and it is comfortable in about an hour and no problematic odors.

 

[rayra]

By the time it's roofed you can paint it. The block is dry, only the mortar has any moisture & that will be dry by the time the roof & doors are on. On the outside it's a good idea to give the stucco plenty of time to dry before painting. Your stucco guy can tell you how long.

A good bock / mortar bond is not - should not - be done with dry block. You should give the wall at least weeks to cure before you seal it off with paint, especially if the other side is already likewise sealed.

 

[bb29510]

first coat dryloc, sorry got brain fart with dryvic which is a stucco cooating

 

[bb29510]

first coat dryloc

 

[PopcornSutton]

Without a doubt, a good high solids block filler is the key. And it takes work to get it in all the pin holes. Some painters spray the block fill, but always back roll to ensure all the holes are filled. Finish paint will not fill the pin holes.

 

[Shiftless]

Some painters spray the block fill, but always back roll to ensure all the holes are filled.

THIS ^^^^^^^^^^

 

[PT Doc]

The stucco is not color impregnated?

 

[slim39]

Thanks. That's about what I figured. I'm not worried about the exterior.

I just wanted to get the interior painted before any of the finish work. Sounds like I can time it pretty well. I'd only need a day - maybe two to get it primed and painted.

I just didn't want to rush it and trap any moisture. But yes, since it's just the mortar joints it should dry fairly quickly I'd guess.

 

[slim39]

I painted inside my block with dry lock paint 25 years ago and l am very happy dry as a bone all weather I live in PA Slim 39