Reading lots of information about SIP panel housing and different types of MGO board used to manufacture them, from what I can tell MGO sulphate base board is the way to go as it has some qualities that make it better that the MGO chloride base boards. The biggest problem with MGO seems to be the joints cracking due to moisture, temperature, etc. and not able to find the best way to join the panels with joint compound to prevent this. I’m looking for any information that may be helpful in fixing this problem such as an elastomeric joint compound or any other material that has been tried with good results. Gyprock base coats will stick to MGO board, however there seems to be a lot of factures in getting this write. From what I have read about gyprock base coats is you need to have longer drying times due to MGO absorbing moisture and room temperature being an issue in drying compound out too quickly which will cause joint to be weak and breakdown. Has anyone used a product with success in fixing this issue? Don’t want to build a SIP home and have these ongoing issues. Any help would be greatly appreciated.
SIP (structurally insulated panels) joints cracking
(7 posts) (4 voices)-
Bushwalker
MemberIf cracking is an issue with gyprock on MGO boards, then I wouldn't use gyprock attached to the MGO.
Have an expert plasterer apply a mesh and hard plaster the walls.
Posted Tuesday 26 Sep 2017 @ 11:31:10 pm from IP # -
Gleno767
MemberNot putting gyprock on MGO boards, using gyprock joint compound such as base coat 45 or base coat 60 that will adhere to MGO but cracking due to application methods, humidity and temperature etc. trying to find a jointing compound or method to use between the boards to prevent cracking.
Posted Wednesday 27 Sep 2017 @ 12:53:13 am from IP # -
Johnnojack
MemberAre you using tape over the joint?
Posted Thursday 28 Sep 2017 @ 4:10:01 am from IP # -
gazmo88
MemberWe used Magroc panels. These panels contain chloride
We have had no issues with our walls, although we had a few with the roof panels courtesy of a roofer who, in a just world, would have been drowned at birth.
Our joints were first filled with cornice cement and then taped with Fibafuse tape (glued with cornice cement) then a further coat of cornice cement.
This was Finished with a slow dry powder mix topcoat - Boral 550.
Like I say this has resulted in no cracking issues.
Our roofs are covered in colorbond but the eaves are just the underside of the magroc panels. We put a thin alloy strip across the gaps approx 60 mm wide which was attached with a few ss screws and Sokaflex 11FC . This was after painting so the paint and the sika keep the alu off the magroc. No issues with these either but this technique would allow a good deal of movement before it would become evident . This was chosen mainly because it was the fastest technique.
On one early pavilion we tried doing the eaves with cornice cement, a mesh tape and a dulux render. This did not work well either on the Magroc or the UBIQ panels we used for the barge boards.
We got a few micro cracks on the ceilings which was not the fault of the panels but an idiot roofer - a long unpleasant experience that I won't bore you with. There is " an old painters trick" according to our plasterer for dealing with this. Apply a small amount of no more gaps to the crack. Quickly spray with water from an atomiser and then tool with a pallet knife. The idea is to leave a thinish film of no more gaps across the cracks. Then paint. This should cope with a fair amount of movement but you need to wonder why you are getting movement. Seems to have worked for us.
Oh our panels are glued and screwed. 50,000 coated screws. You would probably know the glue as Gorilla Glue, but we get it from ERA polymers in 20 litre drums. This is serious glue. The EPS edges are also glued/sealed with ICCONS expanding foam.
I cannot comment on Sulphate MGO panels, you need to do your own research and make your own choice.
Good luck
Posted Friday 29 Sep 2017 @ 8:31:30 am from IP # -
gazmo88
MemberAs chance would have it I was down at the Dulux trade centre last week, looking for the right thing to paint our masonry heater.
(after a long discussion, Porters Lime Wash which will let it breathe maximally)As things were quiet I asked about suitable paints for dealing with cracking.
They suggested Dulux AcraTex Elastomeric 201 which has apparently got amazing stretch ability and despite the product description is suitable for interior as well as exterior use, and can be rolled (if you don't mind a bit of stippling type texture ) or sprayed.
They did also mention that its quite expensive, but I did not price it.
I hope this helps you.
Cheers
Posted Wednesday 25 Oct 2017 @ 5:40:08 am from IP #