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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorwoodgnome
    • CommentTimeJan 20th 2015
    I have about 120sqM of Cedar cladding to go over standard 7.5N concrete blockwork.
    Battens 38mm deep.
    Apart from the obvious plugs and screws, i was thinking hilti gun or similar.
    Has anyone used one for this?
    I can hire a paslode version quite cheaply but i think the max length of fixing is 70mm and not sure if this is enough.
    Plugs etc are fine but i was trying to speed the process up!
    Rule of thumb for fixing timber is 2.5 x the depth of the timber being fixed. So 38mm x 2.5 = 95mm.

    Seem like very deep battens to me, Is it to allow a good fixing for the Cedar?
    • CommentAuthortony
    • CommentTimeJan 20th 2015
    Hilti gun tends to split timber and mess it up.

    Screws without plugs would make it easy, they drive straight into the concrete after a hole has been drilled. I would use screws and red plugs, 5.5mm drill and no10 screws, I am very fussy about the plugs only one type are any good.

    I wouldn't use 25mm battens, how about 38x38? Even 47x38
    • CommentAuthorGreenfish
    • CommentTimeJan 21st 2015
    My builder/carpenter used screws and plugs to attach my battens, insisted the only way for quality job. Cedar vertical so battens and counter battens of regularised 38 x 25 (like the roof battens). Cedar cladding nailed by hand too using ss nails (corrosive marine climate).
    • CommentAuthorDarylP
    • CommentTimeJan 21st 2015
    ... have you thought of drilling through the battens in situ, then fixing with masonry screws? They might hold in the block? depending on it's 'friablility'?

    Good luck..:smile:
    • CommentAuthorwoodgnome
    • CommentTimeJan 21st 2015
    Thanks for the replies.
    Mike, you are right regarding the depth of the battens. Cedar fixings should be 2.5 x depth of cladding of 2x if using ring shanks. My cladding is 18mm thick, so 38mm batten to get fixing using stainless ring shanks.
    I think ill go with plugs and 100mm screws...seems to be the safest method.
    DarylP im not too sure on the longevity of masonry screws as builder mate has had some work loose.
    You could use "tapcons" - these are masonry screws that don't need any plugs - these are fine so long as there's no shear load requirement. These grip incredibly
    strongly too.


    Paul in Montreal.
    • CommentAuthorCWatters
    • CommentTimeJan 22nd 2015
    Screwfix also have a range of concrete screws that don't need a plug. Put the screws into the blocks not the mortar. They have a T30 head which is much better than a regular slot/Philips. Might help to have two cordless drills on hand, one with a drill bit fitted and the other with a T30 bit (or some sort of quick change system).
    • CommentAuthorrevor
    • CommentTimeJan 22nd 2015
    I've done a similar job recently. I used fischer 8x50 plugs and 6x 100 stainless screws. I have found that cheaper plugs do not hold as well as the fischer ones in concrete block the larger size gives much greater surface area contact with the hole in the block. Also found useful to cut the thread first in the plug by using a same size steel screw, as the stainless ones can bend and even break when they are driven in. I would not use a concrete screw sometimes called thunderbolts in anything other than solid brick or dense concrete e.g. padstones. I used to use through bolts in concrete building blocks until I did some tests and now would only use resin anchors if fixing something large to building blocks.
    • CommentTimeJan 23rd 2015
    V gd info, thanks all
    Ive used a nail gun , spiking galv shanked nails on the angle in alternative directions, this was on ligt weight blocks though. set the pressure right and you wont split the wood.
    plug and screw for me on a denser block
    • CommentAuthorwoodgnome
    • CommentTimeJan 25th 2015
    Bit off topic, but i planned to fix membrane between battens and blockwork. Is this a good idea?
    • CommentAuthortony
    • CommentTimeJan 25th 2015
    breather one, yes but not essential
    Can't see much point putting a breather membrane there unless you counter batten.
    I think so. would be interest in other views.
    • CommentAuthorjamesingram
    • CommentTimeJan 25th 2015 edited
    Ive done it with using lightweight blocks not suitable for external exposure. Idea being to give a bit of additional protection if the cladding leak at all. I see your point mike.
    Perhaps a bit pointless on external blocks
    • CommentAuthorwoodgnome
    • CommentTimeJan 25th 2015
    My reasons for the membrane were
    1 Its 200mm full fill cavity and a very exposed site.
    2 It may help reduce dampness/ moisture which might help stop cedar blackening from the back. I am treating cedar with oil both sides.
    They put pro clima membrane on the Golcar Passive house behind the cladding.
    • CommentAuthorrevor
    • CommentTimeJan 25th 2015
    When I did my battening they were over kingspan k5 insulation and their recommendation in this instance was to put a breather membrane directly over the insulation presumably to avoid deterioration should the cladding let water through. On an external toilet I built in block insulated cavity wall I did not put any felt on the blocks as there was no real reason to do so. That was 5 years ago and there has been no issues with leaving it out. One thing I would do is close off the bottom gap between the battens with a fine mess ( I used plastering corner beading) in order to stop insects nesting. You may also want to do the same at the top but when I discussed my situation with my BCO he did not believe it to be necessary so did not do it.
    Reason for the counter batten is that the Breather membrane Certification (at least brand leading ones) specify the air gap either side of the membrane for it to work...
    • CommentAuthorArchmoco
    • CommentTimeJan 30th 2015 edited
    I used a mixture of fisher frame fixings and express nails, both worked well for my 44x44 battens
    • CommentAuthorwoodgnome
    • CommentTimeJul 13th 2015
    Thought I'd update this thread.
    In the end we nailed the battens temporarily in place through the mortar joints. Once we had done several rows of battens, we then drilled through in situ and used plugs and stainless screws.
    • CommentTimeJul 13th 2015
    So is it screwed into the mortar joint?
    • CommentAuthorowlman
    • CommentTimeJul 13th 2015
    Maybe the initial nailing was into the perpends?
    • CommentAuthorwoodgnome
    • CommentTimeJul 14th 2015
    We nailed into the block work joints which was 6:1:1 sand/cement/lime.
    We then went back and fixed the plugs and screws into the blocks, not the perps/,bed.
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