I'm helping out a local charity who are putting up a large wooden pavilion = (about 12 x 7m including a veranda). The foundations are in place as speci= fied by the building supplier and we expect to have the building delivered = and put up next week.
The pavilion will rest on a concrete base with rows of 2 courses of enginee= ring bricks and a DPC on top. The pavilion supplier specifies that the buil= ding needs to be anchored to the concrete base at approximately 1.2 metre i= ntervals, but I haven't been able to get a spec from them for the type of s= trap/bracket to use for this and our builder isn't sure either.
Any suggestions? Have seen things like
formatting link
which might do but don't = think these are for the intended purpose.
(about 12 x 7m including a veranda). The foundations are in place as specified by the building supplier and we expect to have the building delivered and put up next week.
engineering bricks and a DPC on top. The pavilion supplier specifies that the building needs to be anchored to the concrete base at approximately 1.2 metre intervals, but I haven't been able to get a spec from them for the type of strap/bracket to use for this and our builder isn't sure either.
formatting link
might do but don't think these are for the intended purpose.
Assuming the building has timbers that rest upon the DPC, I would drill right through the timbers, the bricks and deep into the base, then use resin bonded bolts to hold the timbers down. That will hold the building against the strongest wind.
You really need to attach your anchors to the timber uprights, not just to any short horizontals that span them. That suggests that drilling through the timber as described above won't work. You obviously want the anchors inside, because they won't look nice outside. Will you get a chance to fit them before the floor goes down? I doubt it, somehow. Maybe you should drill through as described above, but add a 'V' of two diagonal braces so the forces are transferred to the timber uprights.
(about 12 x 7m including a veranda). The foundations are in place as specified by the building supplier and we expect to have the building delivered and put up next week.
engineering bricks and a DPC on top. The pavilion supplier specifies that the building needs to be anchored to the concrete base at approximately 1.2 metre intervals, but I haven't been able to get a spec from them for the type of strap/bracket to use for this and our builder isn't sure either.
formatting link
might do but don't think these are for the intended purpose.
They would probably do. Assuming the building is clad inside and out, so that the framing is concealed when it is finished, I would be inclined to bolt the short leg down through the bricks into the concrete with resin anchors as Nightjar suggests, with the long leg running up the verticals and screwed to them with several meaty screws.
If it is somewhere fairly exposed, I think I might go up in size to something like 50 x 6 mm mild steel strip, bent into an L shape by a blacksmith or by heating with a propane or oxyacetylene torch. Maybe 150 mm for the short leg with two 12 mm bolts, and 500 mm for the upright. I speak from experience of having a double field shelter (about 8 x 4m) overturned. After that, I cast loops of 10 mm studding into concrete footings and tied these to the roof structure with galvanised steel cable and turnbuckles. I decided on this after using the British Standard to calculate that the 30 year wind was generating about 2 tons of lift on the pitched roof.
>> which might do but don't think these are for the intended purpose.
Most large wooden structures I have seen are built using timber base plates, with the verticals attached to the top of the base plates. My advice is based upon the assumption that is how this building will be made.
The base plates in my large wooden shed are on top of the floor and the fixings go through both.
Yes, that's the norm here (where most structures are built using wood); J- bolts are set into the foundations when they're initially poured, and then the (wooden) sill plates attach to these, with the uprights attached to that.
If the foundations are already in place then concrete wedge anchors can be used instead.
Somewhere around 1.2m sounds about right from what I've been told, although when I was replacing rotted-out sill plates in the workshop building I found that they'd only anchored every 4m or so (but it had stood like that for 60 years). I think I put replacements in every metre.
Many thanks to everyone who suggested ideas. Talked to our local BCO who s= uggested bolts through the bottom rail of the timber frame and the engineer= ing bricks to the concrete. The bricks are the hollow type so drilling shou= ldn't be too arduous. We could perhaps add anchor straps at the corners if= we're worried about the frame splitting.
I guess the alternative would be to use straps to the vertical timbers (at =
2.4m intervals) and bolt straight through in between. Will discuss with ou= r builder.
I once owned 9and lived in) a wooden house for a while (120 square metres).= It was a 'log cabin' type and had no uprights at all; all the timbers wer= e horizontal. It had a few steel rods going from top to bottom inside th= e walls which squeezed the whole thing together vertically and had to be re= tightened as the wood shrank over the years.
It stood on a series of concrete pillars but was not attached to them in a = any way. Robert
In the meantime the building is up, looking good. Talked to the builders w= hile they were putting it up - in their experience the main vulnerability i= s a gale blowing straight towards the veranda (since this faces SW this is = quite likely to happen at some stage during the winter, although we're in a= sheltered inland part of SE England). They suggest fixing the veranda sup= port struts to the concrete base urgently (this can be done with simple L-s= haped brackets), and that fixing the rest of the building is less important= .
To go through the timber frame and the two courses of engineering bricks an= d into the base will require bolts at least 300mm long. The Multimonti bro= chure seems to show availability up to 400mm, but the longest I've managed = to find in reality is 140mm, from Screwfix. Anyone seen any 300mm+ Multimon= ti bolts (or equivalent) for sale?
SDS drill through your frame and engineering bricks intro your base, and resin fix studding of appropriate beefyness into the base. Washer and nut tightened down finishes the job. Much more effective than multi-monti and dramatically cheaper.
Thanks, Andrew - will suggest that to our builder when I see him. A combination of studs to fix the frame and brackets to fix the veranda support struts should do the trick.
(about 12 x 7m including a veranda). The foundations are in place as specified by the building supplier and we expect to have the building delivered and put up next week.
engineering bricks and a DPC on top. The pavilion supplier specifies that the building needs to be anchored to the concrete base at approximately 1.2 metre intervals, but I haven't been able to get a spec from them for the type of strap/bracket to use for this and our builder isn't sure either.
formatting link
might do but don't think these are for the intended purpose.
Have you asked building control what will be acceptable to them?
Yes, the BCO's suggestion is bolts through the sole plate of the framework,= although the pavilion manufacturer's view is that the veranda is the most = vulnerable part of the building in high winds so the support struts need to= be tied down. Will probably go with 300mm studs (M10 or M12) round the ma= in building and an L-shaped anchor strap or bracket on the veranda supports= . Just need to confirm with our builder when we see him (he's away until W= ednesday).
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.