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RSJ Supporting Floor Joists Question


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#1 muffin

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Posted 18 October 2006 - 09:23 AM

I am currently having a first floor extension built over a single story Garage/Utility room attached to the side of a two storey house.

Builder has just installed the first of 4 required RSJ's, this one supports the new first floor joists.

Floor joists run along length from front to back (7.6M)therefore the RSJ splits this span in two. Floor joists are notched and inserted into each side of the RSJ so that it is not visible at ceiling level (Joists: approx 225mm x 45mm, RSJ: approx 200mm x 140mm)

My question is about the installation of the RSJ, as there are cavity walls each side of the garage (100mm wide block with a 100mm cavity - one is the two story side of the house and the other is the gable end of the garage with a total width between them of 3.25M)the builder cut a square hole through one skin of the cavity either side of where the rsj was to sit, then cut the rsj to the width of the floor plus 100 mm either side, because of the 100mm depth of the cavity he was able to fully insert the rsj 200mm on one side and then move it back so it was resting 100mm on both sides, he then simply packed under the rsj so it was at the right height before installing the floor joists.

Is this method acceptable or will it cause problems over time because no padstones were used?

the RSJ is only supporting the floor and nothing else.

#2 saddened1

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Posted 18 October 2006 - 12:56 PM

I would be happy with that if I were doing it, providing the packing is effective.

#3 bobg

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Posted 18 October 2006 - 08:12 PM

Me too.must have five words.

#4 derekfarr

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Posted 19 October 2006 - 07:14 AM

Area of RSJ resting on bwk = 140 x 100 = 14000mm2
If crushing strength of brick = 1N/mm2 then load that one end of RSJ can take is 140 x 100 = 14000N which is 1.4 tons. Since there are 2 ends to RSJ total load that RSJ can take is 2.8 tons. Assuming bricks have have a crushing strength of at least 3N/mm2 RSJ allowed to take 3 x 2.8 = 8.4 tons. Can you get 5 cars in your bedroom???

#5 muffin

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Posted 19 October 2006 - 10:13 AM

Thanks! your replies are reassuring

Saddened1: the packing appears to be pieces of some sort of cement particle board about 5 or 6mm thick (not sure of the name)probably salvaged from the edge of the original roof (used underneath edge roof tiles to hold cement in place) total height of packing is approx 25mm.

Derekfarr: Thanks for the calculations! the 1st floor room is to be an upstairs Lounge/Games room with a second floor mezzanine at attic level overlooking it, so the heaviest thing I can foresee in it is a Pool Table!

#6 caliwag

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Posted 19 October 2006 - 03:37 PM

Five slate bed snooker tables!
Wag

#7 borat37

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Posted 25 February 2010 - 05:48 PM

i have to fit two u beams side by side that are both of the same size. the architect has asked for timber between the beams and bolts through at 600 centres.what wld be the best way for me to fit the timber?

#8 temp

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Posted 25 February 2010 - 11:44 PM

Ask your architect if it's not clear. Did he specify what size bolts?

Can you get a drill bit long enough to go through both beams and the wood in one go? If so I'd clamp it all up and do it that way.