Concrete Block Wall Help

[Justin McCurdy]

Does anyone know of any material that can be applied over a PAINTED cement block wall to cover the seams and make the wall more uniform? My dad is trying to finish his basement but the search has yielded nothing. He is looking for quality stuff that will not flake and chip over time.

Thanks,
Justin

[Lee Koepke]

what it sounds like you are trying to do is 'float' or 'skim coat' the wall to cover the mortar joints.

as for the existing paint, alot depends on the condition of the paint, what kind of paint and how old it is. various primer and prep techniques would be appropriate depending on the condition.

one thing to think of, you essentially will applying a thin cementious coat over a substrated engineered to move. thus you may be subject to future cracking at the joints.

I am not sure if I am hitting your question or not ....

[Justin McCurdy]

what it sounds like you are trying to do is 'float' or 'skim coat' the wall to cover the mortar joints.

as for the existing paint, alot depends on the condition of the paint, what kind of paint and how old it is. various primer and prep techniques would be appropriate depending on the condition.

one thing to think of, you essentially will applying a thin cementious coat over a substrated engineered to move. thus you may be subject to future cracking at the joints.

I am not sure if I am hitting your question or not ....

Exactly. The paint was primered and finished with a latex based white paint probably about 10 years ago. My dad is looking to 'skim coat' the wall to cover the mortar joints.

As for the question, I need to know what to use "product-wise" to complete the task of skim-coating.

Thanks,
Justin

[Rob Russell]

Does anyone know of any material that can be applied over a PAINTED cement block wall to cover the seams and make the wall more uniform? My dad is trying to finish his basement but the search has yielded nothing. He is looking for quality stuff that will not flake and chip over time.

Thanks,
Justin

Sure - sheetrock.

[Lee Schierer]

I recall hearing about a thick wall paper material that could be used to cover concrete block walls to level out the joints. Check this site concrete covering (http://www.roosintl.com/glass_textile_wallcovering/index.htm) for one source. It was a cctually used on TOH according to the site.

[Justin McCurdy]

Lee,

It calls for the walls to be smooth before application. I need to know what to use to make the walls smooth in the first place.

[Matt Meiser]

Rob stole my sarchastic, but also serious, reply. That would allow putting up some insulation too. The obvious drawback is cost.

[Mike Marcade]

Sure - sheetrock.

I was thinking the same thing. :D

[Justin McCurdy]

To answer the sheetrock remark, there is no way in he double hockey sticks that sheetrock is going up on basement walls in anyone in my family's homes because of MOLD. If the walls can't breathe, bad things happen. My cousin's house had this problem and now the doctor's can't cure her of any of the magical diseases that appear month to month. She has missed 3 years of high school and is not getting better. So, moving on...

[Matt Meiser]

In the PDF on Concrete Block installation (http://www.roosintl.com/glass_textile_wallcovering/pdf/problems_block_walls.pdf) on the link Lee provided they actually talk about installing it over a painted surface. It says to scrape or sand the walls to knock off any high spots, clean the painted surface with TSP and then smooth with Durabond 90 (http://www.usg.com/navigate.do?resource=/USG_Marketing_Content/usg.com/web_files/products/prod_details/SHEETROCK_Brand_Durabond_Joint_Compound.htm) which is a setting-type joint compound. If they are bare, they want you to prime first. Dave Richardson used something like that when he did some mud work in my bathroom and it dries extremely hard compared to regular joint compound. The 90 part refers to the set time.

[Rob Will]

Sure - sheetrock.

Rob and Mike have the right idea....drywall.
Here is a product that I used in my basement several years ago. It is working flawlessly. It is styrofoam insulation that has a rabbet in the edge to accept a 3/4" furring strip. Put it up with tapcons. It makes for a very solid-feeling wall. Blocks moisture - no place for mold to grow.

http://www.dow.com/styrofoam/na/res-canada/products/styrofoam/wallmate_slotted.htm?view=print

Rob

[Rob Will]

To answer the sheetrock remark, there is no way in he double hockey sticks that sheetrock is going up on basement walls in anyone in my family's homes because of MOLD. If the walls can't breathe, bad things happen. My cousin's house had this problem and now the doctor's can't cure her of any of the magical diseases that appear month to month. She has missed 3 years of high school and is not getting better. So, moving on...

Sheetrock works fine in a basement if the moisture is blocked. See my other post about the DOW styrofoam panels. My basement was very wet before I started. Installed some drainage on the outside. ZERO mold.

One of the main causes of MOLD is water vapor condensing on cold surfaces. Sometimes, adding better insulation can decrease MOLD problems.

Rob

[David G Baker]

There is a Fiberglass roll product designed for covering plastered walls with cracks and I believe it is also designed for covering wood paneling, it may work on a block surface if it is prepared correctly. Do a Google search for Fiberglass wall covering.

[Paul Simmel]

Justin,

The seams only (joints) will not be able to be filled in with any desirable result. The block’s texture is just too rough. It would look much worse than just freshly painting it.

Plaster is the only thing, over the entire 100% of wall surface which will result in a nice interior wall.

I know you said the walls were painted, and that you didn’t ask for other solutions, but the drywall options mentioned (short of a nice plaster job) will make the walls look like interior wall should look. It can be furred out with treated lumber, and you can leave breathing spaces along the bottoms and tops for air movement. The baseboards can be left slightly up, and any crown or trim can be left slightly shy of the ceiling… hence, breathable cavitys between the furring.

The liner option is a good option as well. I’ve used it for many applications, professionally. Filling the seams and all that with DuraBond 90 (or 45) is a must. But after the liner is up, it too would need to be primed and then skimmed 100%, sanded, and primed again… and then your finish painting. Think of the liner as one huge piece of drywall tape that was pasted to the wall. It will need to be skimmed and carefully sanded in the same fashion. If you sand through to the primed liner (inevitable) at least the primer will help prevent “the fuzzies”.

It’s a HUGE undertaking if it’s done right, but will yield very desirable results.

The above liner method is primarily used to rehab old, spider-cracked plaster walls in older homes. Those who do this work aren’t cheap… nor should they be. It’s grueling work.

So there you go. Plaster, drywall, liner (will look like plaster).

[Justin McCurdy]

Thanks everyone for the replies! I'll relay the info to my father and see what he decides to do.

Best Regards,
Justin

[Perry Holbrook]

I just used a product called " Thoroseal "or something close to that to shim coat a pre-painted exterior block wall. You find it in the masonary section at Home Depot. It's actually a waterproofing product but did a good job to cover up the mortor joints.

You do need to keep in mind the waterproofing property. It will seal the wall on the inside of a basement and could keep moisture behind the wall which could cause a problem.

Perry