# Mounting to Hardie Board



## A Little Short

I need to mount a small disconnect (spa) possibly to Hardie board siding.
What is the best way to drill and mount to it?


----------



## telsa

It's closer to cinder block than anything... with fibre added.

Can you drill clean through and attach fender washers and lock nuts ?

I would not trust screw threads to last.

HIlti makes some outstanding toggles that support 1/4-20 hardware.

I'd use them if I couldn't reach around to the back side.


----------



## A Little Short

telsa said:


> It's closer to cinder block than anything... with fibre added.
> 
> Can you drill clean through and attach fender washers and lock nuts ?
> 
> I would not trust screw threads to last.
> 
> HIlti makes some outstanding toggles that support 1/4-20 hardware.
> 
> I'd use them if I couldn't reach around to the back side.


Can't drill clean through, there is a finished room on the inside.


----------



## Anathera

Lag bolts would be ideal if you could hit a stud, I've had some luck with those big silver he head screws or toggles into the voids like tesla said

Sent from my SM-G900R4 using Tapatalk


----------



## CADPoint

Reading up on Hardie Board there is a 10 year transferable limited warranty on the product. 

As ugly as it might be consider a free standing 7/8" stainless steel Unistruct and matching hardware. JMO

Hardie Board


----------



## Cow

Is there plywood behind it?


----------



## splatz

The thing is you don't really want to clamp down on the hardie board, it is crumbly and it's not a flat surface. You want to attach to the sheath under the hardie board. 

Toggles won't work, but it will be easy with snaptoggles. 










These require a half inch hole. What I'd do is start the hole with a 1" bit, but go just until you're through the hardie board, stop when the bit touches the wood. A spade bit will work but a 1" hole saw might be a little safer, start it in reverse to score the hardie board first, then drill the right direction. 

Then drill through the wood with the half inch spade bit, the point of the bit following the pilot from the larger bit to keep the holes concentric. 

Use a stack of 1/4" x 1" fender washers as a spacer on each bolt to get you out past the hardie board so you box is attached to the wood, just out past the siding. This way it will be strong and plumb. The box won't be touching the hardie board. 

Put the bolts through the box, put the stack of washers on, snug the washers up to the box, and put a piece of masking tape around to hold them in place until you get the bolts started. Get all four bolts started, tear off the tape, hand tighten one by one getting the stack seated in there right. 

It's quick and easy, it will take less time to do than it took to read all that


----------



## TRurak

Why not use screws long enough to fasten to the sheathing under the hardie board??


----------



## theJcK

Id toggle strut to it then.. anchors and screws are useless. Almost every building ive done in a decade has this siding but I get benefit of doing it ground up a lot of times.


----------



## 3D Electric

There is strand board under the siding. Just use a 2 - 2 1/2" screw and be done with it! 👍


----------



## A Little Short

TRurak said:


> Why not use screws long enough to fasten to the sheathing under the hardie board??


I'm not sure what is behind the Hardie. It's something either real thin or the Hardie is straight to the studs.


----------



## TRurak

A Little Short said:


> I'm not sure what is behind the Hardie. It's something either real thin or the Hardie is straight to the studs.


Ok. You need toggle bolts or snap toggles. How big will the disconnect be?


----------



## Cow

A Little Short said:


> I'm not sure what is behind the Hardie. It's something either real thin or the Hardie is straight to the studs.


You should be able to see what's under the siding if you bend down and take a look at it right where it meets the foundation?


----------



## AK_sparky

I think it really depends what's behind the Hardie. Figure that out first.


----------



## MikeFL

Are you talking about Hardie Plank siding or concrete board that tile gets laid on? I can't imagine tile backer board being left exposed with no finish over it.


----------



## A Little Short

MikeFL said:


> Are you talking about Hardie Plank siding or concrete board that tile gets laid on? I can't imagine tile backer board being left exposed with no finish over it.


Siding


----------



## 3D Electric

A Little Short said:


> Siding


If it's siding then there has to be an underlayment behind it. So there is strand board. Just use long screws


----------



## hardworkingstiff

I like the idea of using strut, but instead of building a free standing support, I think you can find the studs and support the strut with a long screw into the stud.

I guess it's the commercial side of me coming out. :laughing:


----------



## A Little Short

3D Electric said:


> If it's siding then there has to be an underlayment behind it. So there is strand board. Just use long screws


This isn't the siding around the house. The area used to be a garage door but was framed in and french doors put in. The Hardie is just the trim around the doors. I can't see the bottom to see what's under it but judging from the pics I was sent it doesn't look thick enough to have much, if anything, behind it.

I'm going to try my best to get the customer to let me mount the disconnect/equipment somewhere else so I don't have to worry about the Hardie Board.


----------



## papaotis

if the hardie is just the trim im thinking its not cement board? hardy makes other materials


----------



## 3D Electric

A Little Short said:


> This isn't the siding around the house. The area used to be a garage door but was framed in and french doors put in. The Hardie is just the trim around the doors. I can't see the bottom to see what's under it but judging from the pics I was sent it doesn't look thick enough to have much, if anything, behind it.
> 
> I'm going to try my best to get the customer to let me mount the disconnect/equipment somewhere else so I don't have to worry about the Hardie Board.


It doesn't matter. Hardie board is not strong enough to support its own weight, it would have huge waves in it. It has to have something flat behind it to be nailed to. Usually 1/2" strand board. Sometimes it's as little as 3/8" but that would still make it very wavy.


----------



## The_Modifier

A Little Short said:


> I'm not sure what is behind the Hardie. It's something either real thin or the Hardie is straight to the studs.


You're over thinking it. There is usually only strapping behind it in an opposing direction (up and down). Use 1-1/2" to 2" screws to mount. They will penetrate through the board and into the sheeting behind as mentioned before. :thumbsup:


----------



## A Little Short

I talked the HO into letting me mount the equipment elsewhere.

Thanks for all the suggestions, I'll "sav-um" for another time!


----------



## telsa

Over the years, it's amazing how many problems evaporate after the customer is talked out of a seriously bad idea.

( Any running scheme that's going to bust my ^%$#. )

My personal favorite was moving a heavy isolation transformer down from the second level -- to the concrete slab. ( 'Moving it' in the design phase -- not physically. )

My second favorite was placing the house panel next to the Service. The customer was thinking ( not very successfully ) about locating said panel half-way across the building. ( $4,000 down the drain. )

So it goes.


----------

