Visti Posted February 11, 2020 Posted February 11, 2020 We're adding some additional elements to our building and are trying to spec out the size of the flitch beams that'll be needed for the job. It is a 5.8m span between the ends of the beams (in blue), with the partitioning wall only able to transfer about 0.39kN/m2 down to the pozi joists below. Domestic floors are required to support a dead load of 0.6kN/m2, and imposed load of 1.5kN/m2... but is that overkill for a storage mezzanine? Anyone dealt with something similar?
MikeSharp01 Posted February 12, 2020 Posted February 12, 2020 I suppose you could think of this a bit like a loft where you are not expected to have a dance party. ( which I guess is what the 1.5kn is about) can yiu stiffem up the wall a bit to help?
Russell griffiths Posted February 12, 2020 Posted February 12, 2020 Can you chop the height of the wall down and install a timber beam on top of it 5.8 is a big span.
Visti Posted February 12, 2020 Author Posted February 12, 2020 On 12/02/2020 at 07:02, Russell griffiths said: Can you chop the height of the wall down and install a timber beam on top of it 5.8 is a big span. Expand On 12/02/2020 at 06:04, MikeSharp01 said: I suppose you could think of this a bit like a loft where you are not expected to have a dance party. ( which I guess is what the 1.5kn is about) can yiu stiffem up the wall a bit to help? Expand Problem isn't the partitioning wall, but the joists below. They were supposed to engineer in tolerance to support a wall holding up the mezzanines, but failed to do so. That means the joists supporting the partitioning wall can only support 0.55kN/m. That equates to 0.39kN/m2... not very much I am going to see if I can add in suspension cables from the ridge beam to take some of the rest of the load...
Russell griffiths Posted February 12, 2020 Posted February 12, 2020 What I meant was instal a beam on top of the wall but not imposing a load onto the wall, beam runs front to back, and doesn’t touch the wall. So air gap between wall top plate and beam, cross joists for mezzanine sit on beam not wall, no loads going down all go onto beam which is fitted to front and back walls.
Ferdinand Posted February 12, 2020 Posted February 12, 2020 Can you partly or fully hang it from the roof structure?
ProDave Posted February 12, 2020 Posted February 12, 2020 I had a similar thing except my mezanie only covers one bedroom with it being open to the other. It had been designed like that taking support from the wall between the bedrooms and the floor. One thing I was aware of was bounce in the floor. the logical implication being if you jumped up and down on the mezanine that too might make the floor below that it was ultimately supported on bounce as well. What I did to "fix" this, was purely my own idea with no input from a SE. I cladded one side of that bedroom wall with OSB sheets well glued and screwed to the studwork frame. My theory was I was turning the whole wall into a dirty great engineered I beam and it could probably support the mezanine just by being fixed at each end to the timber frame without putting any significant load on the floor. It worked and you can jump up and down on the mezanine and you feel nothing on the floor below. These are under construction pictures before the wall it rests on got it's OSB skin. 2
MikeSharp01 Posted February 12, 2020 Posted February 12, 2020 On 12/02/2020 at 07:38, Visti said: That equates to 0.39kN/m2 Expand 39Kg / M2 seems ridiculous to me.
Moonshine Posted February 13, 2020 Posted February 13, 2020 On 13/02/2020 at 00:05, Temp said: That's 390kg/m^2 ? Expand No it's not, K is multiply by 1000, but to convert N to kg you need to divide by 9.81, earth's acc due to gravity 3
Visti Posted February 13, 2020 Author Posted February 13, 2020 @Nickfromwales suggested the same as you @ProDave in turning the partitioning wall into a beam effectively with the use of OSB and glue/nails. He also suggested reinforcing the sides of the existing posi joists the same way so that they can better support the partitioning wall. I will be going back to the SE today to see how much improvement that would be! On 12/02/2020 at 08:23, Russell griffiths said: What I meant was instal a beam on top of the wall but not imposing a load onto the wall, beam runs front to back, and doesn’t touch the wall. So air gap between wall top plate and beam, cross joists for mezzanine sit on beam not wall, no loads going down all go onto beam which is fitted to front and back walls. Expand Not a bad idea either! That'll avoid the need to worry about the partitioning stud wall and the joists beneath all together On 12/02/2020 at 09:34, Ferdinand said: Can you partly or fully hang it from the roof structure? Expand Possibly, but not getting a straight answer from them at this time! On 13/02/2020 at 07:48, Moonshine said: No it's not, K is multiply by 1000, but to convert N to kg you need to divide by 9.81, earth's acc due to gravity Expand Yup, afraid one loses an order of magnitude more than one might expect 39kg/m2 isn't much at all to play with when domestic regs require ~60kg dead load plus the 150kg improsed.
Ferdinand Posted February 13, 2020 Posted February 13, 2020 (edited) On 13/02/2020 at 07:58, Visti said: Yup, afraid one loses an order of magnitude more than one might expect 39kg/m2 isn't much at all to play with when domestic regs require ~60kg dead load plus the 150kg improsed. Expand There is always a silver lining. I make that about 50 bottles of beer per sqm, if you can reach it all from the ladder with a system of trolleys. Or Scalextric AND Beer. YES !!! (Yes. I know ... weird measurement. But it is better than the BBC measuring Madagascar in blasted football pitches.) Edited February 13, 2020 by Ferdinand 2
Temp Posted February 13, 2020 Posted February 13, 2020 On 13/02/2020 at 07:48, Moonshine said: No it's not, K is multiply by 1000, but to convert N to kg you need to divide by 9.81, earth's acc due to gravity Expand Oops my bad. Didn't spot the N. 1
Visti Posted February 15, 2020 Author Posted February 15, 2020 Good news is that there is a very cheap resoution after all! And far less technically challenging. Rather than ~£1.5k on flitch beams, Nicks idea of reinforcing the joists beneath the partitioning wall is a green light. It requires some specialist material rather than plywood, but a 45mm thick Kerto S beam affixed with ESCR screws to each joists will reinforce them enough according to our engineer. Only about £200 after delivery fees. 1
ProDave Posted February 15, 2020 Posted February 15, 2020 That solution removes the main advantage of posi joists, the ability to easily run services and pipes etc through the joists.
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