Plastering Cement board and backer board - how to skim coat DIY method with Mapei primer.

Can cement board, backer board, be skimmed with multi finish plaster? DIY attempt with PVA fails but see how to successfully get the job done using Mapei Primer.
Warning: this video contains singing.

[@tribalchav5363]

Came here for plastering, stayed for the tunes!

[@b33zo]

Ha Thanks Richard. Probably a photo-finish between plastering and singing skills..(for last place)! ATB b33zo

[@johncoppock3823]

Thanks John, great video. I've never dared do any serious plastering as an amateur. I guess you have done a fair bit. Of course its an art form, so it must be your singing that does the trick.

[@b33zo]

Thanks for watching John. DIY plastering, like amateur singing, improve with practice. If you don't shoot you don't score. ATB b33zo

[@VelvetCrone]

Thanks! I found a product by Mapei - Primer T, made for just this purpose when I went looking for the one you suggested. Easily available locally here at Lowes in Los Angeles, and very affordable. A few years ago these products were pricey and really hard to find. I'll be giving it a try on a sheet of Durock, and coating it with Potters Plaster #1 for a custom ceramics table I'm making for one of my my daughters in law. Pottery plaster is slightly softer and far more absorbent than anything that would be wall appropriate. I'll let you know how it works out.

[@b33zo]

Thanks for watching MOG. We've come a long way from plastering a bathroom to creating a ceramics table but its nice to hear from LA (where my daughter lives). I once tried to make a ceramic table top in the Gaudi style but ended up with more grouting than tiles. Not a sucess! Best wishes for your project. b33zo

[@grantshortland3907]

I have used sbr as primer on an cement boarded alley ceiling and plastered over it - 2-3 years on no cracks or flaking

[@b33zo]

Thanks for watching Grant. Good to know. I guess SBR and PrimerG are probably made of the same chemicals. I did a fair bit of research at the time and as far as I remember Screwfix forums let me to the Mapei product. Cheers b33zo

[@k1l2z3d4]

You've got a great singing voice.

[@b33zo]

Well thank you Lisa! Who doesn't like singing in the bathroom?! You might like my 'Killing me softly' also on this channel.
ATB b33zo

[@katsudolady5099]

He can sing!
And plaster! The man of my dreams!

[@b33zo]

Ha Thanks kat, also quite ancient but very kind of you to say! ps Salsa Cubana advanced level. b33zo

[@jamesgurgel5795]

A lesson with a show! Thank you

[@b33zo]

Thanks for watching James.

[@ratchriat1716]

I think you did a cracking job on plastering that small sections happy days.

[@b33zo]

Thanks for watching RR. Plastering/rendering is a real craft and not something I know much about.

[@heidistanton4583]

Lovely and very nice singing❤

[@b33zo]

Thanks for watching Heidi. b33zo

[@knowhow8490]

Marvelous job done
Keep up the good work

[@b33zo]

Thanks for watching knowhow. An unusual remark but accepted with thanks. ATB b33zo

[@petermeixler426]

Damn..OG got pipes!

[@b33zo]

ha thanks for watching Peter. Yeah and no auto-tune...b33zo

[@LVCID777]

Good job singing mate!

[@b33zo]

Thanks for your compliment Lucid. Great reverb adds to the fun of bathroom work! b33zo

[@LVCID777]

@@b33zo 😂😂😂 indeed

[@greggferns3278]

You lay in your second coat when your first coat is still wet.Basically thickening the first coat,taking out any dips or slacks and then polish finally with a little water...not too early though.

[@b33zo]

Thanks for watching Gregg and passing on your knowledge. b33zo

[@albertpayne4702]

Sbr also works for priming cement boards or heavy suction backgrounds

[@b33zo]

Thanks for watching albert and sharing your knowledge.

[@realsharpe]

Love his song

[@b33zo]

Thanks realsharpe it's a vital part of amateur plastering.

[@northjerseykevin409]

Great video, thank you

[@b33zo]

Thanks for watching Kevin.

[@Bullsheet_Bob]

I heard that blue grit stuff is really good

[@hannahkentish3026]

Hi, brilliant video, just what I needed, thank you.
A question for you as ee have a similar situation where we have some aquapanel outside of the area we're tiling (bad planning on our part there!)... Will this method of using this primer before multifinish work on aquaboard cement board? Then we will be able to paint over the plaster.
Thank you!!

[@b33zo]

Thanks for watching Hannah, yes it should be okay. The primer can be used on all cement boards and screed floors before tiling or plastering. I tiled up to half way then painted the top half of the wall. You might be able to see the finished job in one of my other videos in that bathroom. Good luck with your project. b33zo

[@roontunes]

People who make multipurpose cement boards say they must be primed with SBR at 5:1 for skimming or tiling.

[@monty1084]

Good job, just the question i wanted to know.

[@b33zo]

Thanks Monty. The Mapei primer is quite expensive but can be used on other jobs as well.

[@caahacky]

Worth watching for the song.

[@b33zo]

Thanks for watching dear friend. b33zo

[@callumbarratt2650]

The STS board, is that the dark blue board they sell in Wickes? Great video, also attempting to figure out how to plaster onto a similar brand

[@b33zo]

Callum thanks for watching. This was the genuine rigid Hardie board made of cement and fiber and not affected by water. The blue stuff is lightweight and more flexible but apparently okay to tile on. Good luck with your project. b33zo

[@chrisharrilal2846]

can I use regular Portland cement to skim coat the cement board?

[@b33zo]

Thanks for watching Chris. I doubt (my opinion as a DIYer) whether sand and Portland cement render would stick to cement board and skim coat almost certainly not. b33zo

[@bill6880]

A nice coat of SBR??

[@fostertop]

Can you whistle?

[@bazm6194]

Use thistle bond and it will stay on

[@b33zo]

Thanks Baz M didn't know that.

[@marcusp905]

Is prima g like sbr?

[@Matteo-jy3ml]

hi, if i use g mapei primer in the presence of humidity what are the consequences?

[@b33zo]

Thanks for watching matteo. The purpose of this primer is to prevent moisture (in plaster) being absorbed too quickly. Humidity would have no effect in this bathroom as the area is completely covered in tiles.

[@restnyoni3064]

I've seen other people using cement fiberboard on the exterior of the building and then using normal cement and plaster sand and then a couple of hours after plastering the cracks start to come out ,so my question is what type of cement is suitable for exterior walls on the cement fiberboards

[@b33zo]

Hi Rest Nyoni and thanks for watching. If I knew the answer I would tell you but as a DIYer I've never faced that situation. Sounds like something Aussie builders or Californians would know more about than UK people. Best wishes b33zo

[@SC-hk6ui]

There are a few products like Cekol C35 that might be of interest. You would want to reinforce the board with mesh, but ultimately if you do not design a system that can move with the sway and expansion of the building, then it will always crack. You need a decoupling membrane to fully avoid cracking.

[@shahminrazali]

⁠@@SC-hk6ui good advice! and what would be a good decoupling membrane for an outdoor situation?

[@SC-hk6ui]

@@shahminrazali nylon mesh.

[@trevornorman9544]

If only my highly expensive plasterer had known this and not sent me on a 1 hour round trip to get PVA glue that then didn't work!

[@jameselliott4019]

What a voice!

[@b33zo]

Ha Thanks James - hopefully in a good way! b33zo

[@shannonsnowdog9482]

What kind of primer?

[@b33zo]

Hi SS that would be Mapei Primer G.

[@zaimhazmin8851]

Damn.. i only lasted 4mins of vid. Ears bleeding

[@b33zo]

Ha thanks for watching @zaimhazmin8851 hope your ears come good. b33zo

[@robhale1357]

Stick to the singing mate

[@b33zo]

Thanks for watching Rob!