HardieBacker 500

[Unregistered]

Afternoon All
Very quick question for you guys. I've got some HB500 to put up onto some breeze block wall. I've read the masonry document from HB but it states the 6mm board:
"...HardieBacker 6mm cement board is simply adhered to the masonry walls using 3 vertical 10mm beads of Grip Fill, evenly spaced across the board. The board is then attached with 9 masonry anchors. Ensure the wall is sound, clean and ready to receive Hardiebacker 6mm. At minimum, the rear of Hardiebacker 6mm Cement Board and the masonry wall must be wiped down to remove all dust. (All existing old dry lining should be removed as it has potential to fail further) Use 6mm x 50 mm masonry anchors with self-embedding head...:
Would it be acceptable to use slightly more GripFill and sightly longer fixings for the 12mm board?
Many thanks for your time

 

[The D]

yes

 

[Unregistered]

Many thanks deano

 

[Dan]

Well that was a quick one.

 

[DHTiling]

That is new instructions on me...?


This is the one i got from hardibacker UK.. View attachment HardieBacker EN installation 200810 masonry walls.pdf

 

[gherkin]

thought I'd register this time round

Anyhow Dave

I received two documents from HB, one a .docx file and the other a pdf (HardieBacker A4 v2 12042010 All Installation Instructions)

Can't upload the docx so here it is:

PRODUCTS NEEDED

1. MASONRY ANCHORS – 9 per board. Use Ø 6mm x 50 mm masonry anchors with self embedding head. Do not overdrive head of anchor, it must be flush with face of HardieBacker® Cement Backerboard EZ Grid® 6mm. The screw should have adequate provision for corrosion resistance.
2. Cartridge based, high strength, gap filling adhesive.
3. Alkali resistant Fibatape.

For the application of Hardiebacker over Masonry walls, Hardiebacker 6mm should be used. HardieBacker 6mm cement board is simply adhered to the masonry walls using 3 vertical 10mm beads of Grip Fill, evenly spaced across the board. The board is then attached with 9 masonry anchors. Ensure the wall is sound, clean and ready to receive Hardiebacker 6mm. At minimum, the rear of Hardiebacker 6mm Cement Board and the masonry wall must be wiped down to remove all dust. (All existing old dry lining should be removed as it has potential to fail further) Use 6mm x 50 mm masonry anchors with self-embedding head. Do not overdrive the head of the anchor; it must be flush with face of HardieBacker 6mm cement board. The screw should have adequate provision for corrosion resistance. This recommendation is intended for use in residential and light commercial buildings. Maximum load carrying weight is 100 kg / m2.

Although having just read through the Installation pdf again (not sure how i missed it first time round) its contradicting. In both instances it uses HB250, however as in the above quote it say to use 3 beads of grip fill, in the pdf it states tile adhesive using a 6mm notched trowel? Now slightly confused

 

[DHTiling]

Hi.. I cannot see how 3 beads of gripfill will provide any support to the boards, as in deflection ... as the boards will not be fully bedded.. imho i would deffo embed into adhesive, then you know it is solid and fully supported..

 

[gherkin]

my thoughts exactly there, thanks for initially pointing it out