Cladding an RSJ in timber

[geraldthehamster]

I want to clad a 5 metre RSJ in inch thick softwood. I'm not sure whether I need to clad it in Fireline first, as BCOs differ, but that's not my question. I have a good idea how to do this (with or without PB underneath), using planks, noggins in the RSJ web, but wondered if anyone had any idea how to do it without any nail or screw heads being visible. I suppose I could cut plugs but I think you'd see them. Anyone had a go at this?

cheers
Richard

 

[joinerjohn]

I wouldn't have thought BCO's would differ much on cladding RSJ's I think they have to be protected from fire. Usually by double boarding with 12.5mm PB. I can't see that softwood cladding is going to be allowed.

 

[freddiemercurystwin]

You can clad it in timber, will just need to be clad in plasterbaord first.

What effect are you trying to end up with?

 

[geraldthehamster]

You can clad it in timber, will just need to be clad in plasterbaord first.

What effect are you trying to end up with?

Something that looks like it could be a tidy wooden beam, although it will be clear that it is really an encased RSJ. Ie a pleasing aesthetic effect rather than fooling anyone.

Cheers
Richard

 

[^woody^]

If you are cladding in timber, then presumably an olde worlde look is what you are after, or at least some sort of uneven hewn look, rather than a dead square box.

You can dent, chip, axe or plane the timber to make it uneven.

You need to mitre the joints so that you don't see edge grain where the sides meet the bottom

You can sink some oval nails for fixings, but make sure that these are used unevenly and not in visible lines or patterns. Or if you are careful with cutting plugs and matching the grain, then you wont see these by the time you have filled, stained and blended these in.

A lot of it comes down to how you fill, stain or finish the timber to blend everything in

 

[geraldthehamster]

If you are cladding in timber, then presumably an olde worlde look is what you are after, or at least some sort of uneven hewn look, rather than a dead square box.

You can dent, chip, axe or plane the timber to make it uneven.

You need to mitre the joints so that you don't see edge grain where the sides meet the bottom

You can sink some oval nails for fixings, but make sure that these are used unevenly and not in visible lines or patterns. Or if you are careful with cutting plugs and matching the grain, then you wont see these by the time you have filled, stained and blended these in.

A lot of it comes down to how you fill, stain or finish the timber to blend everything in

Thanks Woody. I think I'm more after the effect of a Victorian pine or pitch pine beam, which would have been machine cut and fairly regular.

I've since looked at what my neighbour did - he glued and clamped the timber sides to the plasterboard, then fired some pins in, which you can barely see. The bottom piece is glued and pinned from underneath to the sides, and again, you can barely see the pins. Seems to have stayed up Obviously the ends are plastered in as well. The edge grain of the bottom piece blends into the side grain of the side pieces, which might be luck, though a chamfer helps.

Cheers
Richard

 

[imamartian]

put some biscuits into the mitred edges?

 

[ladylola]

How I'd do it if I was attempting this to how you'd like.
Bottom piece fixed to the noggins using metal angle brackets so nothing showing there then side pieces chamfered on the bottom edge so the effect is that of a chamfered beam glued and clamped on thus not being needed to be nailed or screwed , bit more of a faf but doable. Would look nice too if you stopped the chamfer before it enters the wall although it does give you a short section of timber where a joint is more visable.
There are also various types of fireproof paint systems that could be employed after the whole thing is erected
for example-
http://www.rawlinspaints.com/Fire-R...2/index.html?gclid=CIuY2Lfc2qcCFYob4QodeU9G9w

 

[geraldthehamster]

Reporting back - this is what I did:

First I clad the steel in Fireline plasterboard, screwed to noggins
inserted in the web of the joists, with the underneath piece screwed
up into the side pieces and Gripfilled to the steel.


I got three pieces of timber delivered from Howarth Timber, inch thick
nominal (ie 21 mm). Two side pieces were 5400mm x 230mm, and an
underneath piece was 5400mm x 212mm.


First I fixed one side piece. Applied lots of Gripfill, and clamped it
to the plasterboard with several clamps, with short bits of floorboard
used to spread the clamping force. Then I fired several 50mm pins into
roughly where I thought the noggins were.


Removed the clamps after a few hours, and nothing moved. Repeated the
operation with the other side piece. This one needed severe propping
at each end to remove a bow. Took the clamps off the next day, and
again nothing moved.


The underneath bit sat underneath the side bits. Applied PVA
to the edges of the top face of the underneath bit, maneouvred into place with a helper, propped with some bits of wood slightly longer and went along
with the nail gun, pushing firmly up and firing 50mm pins through the
edges of the underneath panel up into the side panels. Once pinned it
wasn't going anywhere.


I chamfered the edges the following day with a belt sander, to remove
irregularities and overhangs.


One end of the steel sits on the outside corner of two internal walls,
the other on an 18 inch nib of the wall that was removed. Therefore I
cut the underneath panel with two 18 inch x 21mm ears on it, to go
either side of the nib, so the "beam" appeared to be the same depth
all the way across..


The good part (apart from everything staying up) is that the heads of
the pins, being self-countersinking, do not draw attention to
themselves.


What could have been better: you don't have to look very hard to see
where the join is. This is partly because of knots in the timber that
disappear half way across the knot, and also possibly because I ran
out of 50mm pins half way through the final stage, and had to do some
emergency proppoing while I found some more, so there are some minute
gap lines. Having said that, the result is acceptable. The wood is a
bit blond at the moment, but three years of sunlight will fix that.


Cheers
Richard