Connecting sole plate to block work with Marmox in between.

[SeanDean]

Hello all I'm at the stage where I'm looking for the best solution to strap/bolt down the soleplate of my TF to the blockwork and I am looking for your opinions/advice.

 

I'm currently looking for one of the following options fixed @ 800mm centres:

 

 - Anchor bolts down through the soleplate.

 - Chemical resin anchors down through the soleplate.

 - Strap bend on the outside of the blockwork going up and over the soleplate.

 - Flat strap on the outside of the blockwork that goes up the studs.

 

Any advice and help would be greatly appreciated.

 

[Russell griffiths]

You can get a strap that does all of those jobs in one. 

Think it’s made by CULLUN timber connectors, it’s basically a strap with a foot on it with a hole in it, so it nails to the stud, pushes down onto the sole plate and bolts through to the underlying blockwork. 

 

With regards spacing this is normally dictated by your racking board layout, so position is at the start and finish of racking boards. 

So up the first stud then on the one 1200 away. 

But that all needs someone far cleverer than me to decide. 

[SeanDean]

14 hours ago, Russell griffiths said:

You can get a strap that does all of those jobs in one. 

Think it’s made by CULLUN timber connectors, it’s basically a strap with a foot on it with a hole in it, so it nails to the stud, pushes down onto the sole plate and bolts through to the underlying blockwork. 

 

With regards spacing this is normally dictated by your racking board layout, so position is at the start and finish of racking boards. 

So up the first stud then on the one 1200 away. 

But that all needs someone far cleverer than me to decide. 

 

Cheers for the info, I have been trying to find the timber connectors you speak of but its proving difficult and I'm just coming across standard straps. I was hoping to just adopt one of the methods, is this wrong and should I be adopting more that one?

 

What are your thoughts on the DPC being pierced when using anchor bolts or resin anchors?

 

I'm not sure what the racking boards are that you refer to, I have researched this but can't find this term relating to timber frame construction.

 

Cheers. 

[SimonD]

16 minutes ago, SeanDean said:

I'm not sure what the racking boards are that you refer to, I have researched this but can't find this term relating to timber frame construction.

 

see also 'sheathing'

[Mr Punter]

Can't the straps go on the inside?  less likely to corrode.

[SimonD]

You can use something like this https://www.strongtie.co.uk/products/detail/sole-plate-anchor/408 - sometimes they're installed fully to the inside like an angle bracket.

Edited March 3, 2021 by SimonD

[Russell griffiths]

Sheathing boards cover the frame. 

A racking board is sort of the same but has a more important role it provides the racking strength to stop the building folding like a pack of cards. 

 

So a sheathing board might just cover up your frame. 

But a racking board covers the frame but also adds structural stiffness, racking boards should have a fixing schedule it’s normally a nailing schedule so one 50mm ringshank nail will be provided every 150mm apart on all studs and sole plates and top plates.  

 

Some walls that need need a lot of added stiffness might have racking both sides. 

 

If I was building any frame I would fully board both sides. 

[Russell griffiths]

Look up Simpson tie down straps. 

[A_L]

7 hours ago, SeanDean said:

I have been trying to find the timber connectors you speak of but its proving difficult

 

@Russell griffiths, Something like this perhaps?

 

https://www.klokow-gmbh.de/en/Fastening/Wood-joints/Tension-anchor/Simpson-Strong-Tie-Hold-Down-HTT.html

[TonyT]

I would use an anchor bolt, either 400 or 600 spacing so there is one fixing per bay.

m10/m12.

 

sds drill bit through the timber into the masonry in one go.

[Russell griffiths]

56 minutes ago, A_L said:

 

@Russell griffiths, Something like this perhaps?

 

https://www.klokow-gmbh.de/en/Fastening/Wood-joints/Tension-anchor/Simpson-Strong-Tie-Hold-Down-HTT.html

This is what I have used in the past, however they can be overkill for the uk market, it depends on your wind leadings and other stuff. 

[Russell griffiths]

24 minutes ago, TonyT said:

I would use an anchor bolt, either 400 or 600 spacing so there is one fixing per bay.

m10/m12.

 

sds drill bit through the timber into the masonry in one go.

This method is perfectly adequate, however your relying on your sheathing board transferring the resistance to other parts of the frame. 

With a tie that is fixed to a stud it uses the stud to hold the frame down, not just the sole plate. 

 

Really down to the engineer designing it and what loads are on it and wind loading.

 

The last stick frame I did was in a cyclonic area so I tend to be a bit belt n braces.  

[TonyT]

32 minutes ago, Russell griffiths said:

This method is perfectly adequate, however your relying on your sheathing board transferring the resistance to other parts of the frame. 

With a tie that is fixed to a stud it uses the stud to hold the frame down, not just the sole plate. 

 

Really down to the engineer designing it and what loads are on it and wind loading.

 

The last stick frame I did was in a cyclonic area so I tend to be a bit belt n braces.  

Agree.

i never work to a minimum specification.

money well spent at the correct time, pays dividends later.

[SimonD]

2 hours ago, Russell griffiths said:

Sheathing boards cover the frame. 

A racking board is sort of the same but has a more important role it provides the racking strength to stop the building folding like a pack of cards. 

 

So a sheathing board might just cover up your frame. 

But a racking board covers the frame but also adds structural stiffness, racking boards should have a fixing schedule it’s normally a nailing schedule so one 50mm ringshank nail will be provided every 150mm apart on all studs and sole plates and top plates.  

 

Some walls that need need a lot of added stiffness might have racking both sides. 

 

If I was building any frame I would fully board both sides. 

 

 Splitting hairs there me thinks ? and potentially misleading and vague. At the risk of being pedantic "sheathing" is both common and formal parlence in modern stick framing. If you doubt what I say here are definitions of timber frame by:

 

1. TRADA:

 

"Timber frame construction uses timber studs and rails, together with a structural sheathing board, to form a structural frame that transmits all vertical and horizontal loads to the foundations. (https://www.trada.co.uk/start-here/timber-frame-construction/)"

 

2. Structural Timber Association:

"Design of timber frame wall panels

The lateral stability of the studs against buckling is provided by either a sheathing material or from the provision of timber blockings i.e. noggins or dwangs at intermediate positions in the stud height, to allow fixing of sheathings or to provide lateral restraint about the minor axis of the studs"

 

Resistance to horizontal actions is provided by the in-plane shear resistance (or racking resistance) of sheathed wall panels which are connected together to act as contiguous wall diaphragms. Racking resistance is covered in part 2. "

(http://www.structuraltimber.co.uk/assets/InformationCentre/timberframeeb3.pdf)

 

There really is no need to double up sheathing to both sides of the studs in most cases for domestic buildings, except perhaps under particular circumstances where you need a specialist shear wall.

 

 

[Russell griffiths]

10 hours ago, SimonD said:

 

 Splitting hairs there me thinks ? and potentially misleading and vague. At the risk of being pedantic "sheathing" is both common and formal parlence in modern stick framing. If you doubt what I say here are definitions of timber frame by:

 

1. TRADA:

 

"Timber frame construction uses timber studs and rails, together with a structural sheathing board, to form a structural frame that transmits all vertical and horizontal loads to the foundations. (https://www.trada.co.uk/start-here/timber-frame-construction/)"

 

2. Structural Timber Association:

"Design of timber frame wall panels

The lateral stability of the studs against buckling is provided by either a sheathing material or from the provision of timber blockings i.e. noggins or dwangs at intermediate positions in the stud height, to allow fixing of sheathings or to provide lateral restraint about the minor axis of the studs"

 

Resistance to horizontal actions is provided by the in-plane shear resistance (or racking resistance) of sheathed wall panels which are connected together to act as contiguous wall diaphragms. Racking resistance is covered in part 2. "

(http://www.structuraltimber.co.uk/assets/InformationCentre/timberframeeb3.pdf)

 

There really is no need to double up sheathing to both sides of the studs in most cases for domestic buildings, except perhaps under particular circumstances where you need a specialist shear wall.

 

 

What’s misleading 

@SimonD

 

its clear from where im sitting, you can chuck a sheet of 9mm osb on the frame fixed with a dozen nails, or you fit it correctly with a nailing schedule detailing the amount  of nails per sheet. 

 

 

Its like lots of stuff you can work to a minimum standard, or do the job better to a better standard. 

 

Sheathing board, racking board 

 

totally different things, you can install racking boards at corners and not fully sheath the wall, if a frame is designed to not have sheathing boards on its outer skin you still need to supply racking support. 

 

 

 

Edited March 4, 2021 by Russell griffiths

[SimonD]

2 hours ago, Russell griffiths said:

What’s misleading 

@SimonD

 

its clear from where im sitting, you can chuck a sheet of 9mm osb on the frame fixed with a dozen nails, or you fit it correctly with a nailing schedule detailing the amount  of nails per sheet. 

 

 

Its like lots of stuff you can work to a minimum standard, or do the job better to a better standard. 

 

Sheathing board, racking board 

 

totally different things, you can install racking boards at corners and not fully sheath the wall, if a frame is designed to not have sheathing boards on its outer skin you still need to supply racking support. 

 

 

 

 

I'm not entirely sure what you're getting at here @Russell griffiths. You're now saying something different from your OP which said:

 

16 hours ago, Russell griffiths said:

But a racking board covers the frame but also adds structural stiffness, racking boards should have a fixing schedule it’s normally a nailing schedule so one 50mm ringshank nail will be provided every 150mm apart on all studs and sole plates and top plates. 

 

What I said was that 'sheathing' is the term typically used in modern timber stick framing to denote a structural component in the timber frame (which, by definition would be done with a proper fixing schedule). This provides the wall with its racking strength. It was to help the OP find the information he was looking for which he'd failed to find using the term "racking."

 

If you don't use a structural sheathing board you do, of course, need something to provide racking strength. But generally speaking:

 

Again from the Structural Timber Association:

 

"The racking wall gains its strength from a wood-based board sheathing material or plasterboard lining material fixed to the wall studs which provides racking stability and sliding resistance by its connection to the horizontal diaphragms and foundations." (http://www.structuraltimber.co.uk/assets/InformationCentre/eb4.pdf)

 

A mere search on google for racking or sheathing will tell you the difference in how those terms are generally used in this context.

 

There are always exceptions and alternative ways to do things. On my current project I have an unusual structural design that uses structural osb lining boards on the inside of the timber frame with no external sheathing.

 

What I've said has nothing to do with minimum or better standards, nor poor workmanship, it's about terminology.

 

If at the end of the day you prefer to use "racking," that's fine by me. I just won't and will stick with "sheathing." ?

[Mr Punter]

20 minutes ago, SimonD said:

On my current project I have an unusual structural design that uses structural osb lining boards on the inside of the timber frame with no external sheathing.

 

I have seen this on a project.  They had some breathable insulation on the outside.  Probably like the Steico stuff.

 

Also, some internal walls have OSB sheathing added for racking strength.

[SeanDean]

On 03/03/2021 at 12:30, SimonD said:

 

see also 'sheathing'

Thanks this cleared it up for me.

 

I have 12mm OSB 3 ply on the outside.

[SeanDean]

On 03/03/2021 at 12:54, Mr Punter said:

Can't the straps go on the inside?  less likely to corrode.

 

Ideally, they would but then that would mean they would need to penetrate the DPM that comes from under the base and laps up over my blockwork.

Is it ok to do this and if so do the areas the straps penetrate need to be taped or sealed up some home?

[SeanDean]

18 hours ago, A_L said:

 

@Russell griffiths, Something like this perhaps?

 

https://www.klokow-gmbh.de/en/Fastening/Wood-joints/Tension-anchor/Simpson-Strong-Tie-Hold-Down-HTT.html

 

These look good, but not cheap also some additional work involved regarding insulation needing to be shaped around them.

[SeanDean]

17 hours ago, TonyT said:

I would use an anchor bolt, either 400 or 600 spacing so there is one fixing per bay.

m10/m12.

 

sds drill bit through the timber into the masonry in one go.

 

Cheers for your input, what are your thoughts/solution on penetrating the DPC?

[SeanDean]

Some really useful responses from you all that have really helped me understand what I need a lot more and the reasons why. 

 

I'm going to work on a solution that includes anchor or resin bolts along with a strap like the one below, I just need a solution for sealing the DPC after it's been penetrated along with sealing the DPM if I put the straps on the inside of the build. Any input would be greatly appreciated.

 

 

[Mr Punter]

12 minutes ago, SeanDean said:

Ideally, they would but then that would mean they would need to penetrate the DPM that comes from under the base and laps up over my blockwork.

Is it ok to do this and if so do the areas the straps penetrate need to be taped or sealed up some home?

 

If you have a section drawing it would be useful.  Handy to see foundation, ext level, slab, insulation ffl etc.

[SeanDean]

2 minutes ago, Mr Punter said:

 

If you have a section drawing it would be useful.  Handy to see foundation, ext level, slab, insulation ffl etc.

Hope this helps

 

[Mr Punter]

I would have stainless steel restraint straps externally.  Have the top bent over top of the sole plate and then rum down the outside 500mm and fix to the blockwork with plugs and stainless screws.  Get them 1200 long and cut in half.  Light duty if the engineer says it is OK.