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We need more people like you "online" RDJ, in the art of structural engineering you can NEVER beat "EXPERIENCE"

Omg I work with many engineers and a lot of them are the same-they are so caught up on how much they think they know because they “went to school” for it, that at the end we the non engineers have to fix all of their un-calculated errors. Save all the verbiage and just let the real knowledgeable workers do the building. If you’re smart, all that institutionalized, doctrination bullshit isn’t required

cool demo. Try the scissors tie. leaving more room for ventilation, and insulation, but not fullly vaulted.

Thank you very much for the video. Im planning a storage floor type of construction for my workshop, which is why i wanted to calculate the maximum allowable weight i could store up there.I study mechanical engineering so i dont have much to do with wood. I had a look at the german version of en 338 and under "Druck in Faserrichtung" (compression parallel to grain, f(c,0,k)) it sais 21N/mm^2, which is obviously much more than the value you used. Is there something im missing here? What is the reason for this huge discrepancy? This is especially confusing because the youngs modulus values are very similar. In the 2016 version of the german en 338 the mean youngs modulus for c24 timber is 11 kN/mm^2 and the minimum is 7,4kn/mm^2. Do your allowable stress values already have a safety factor included in them?

I dont see the structural difference between your steel A-frame and reinforcing the very top with steel triangles, fastened to the ridges. No long steel skeleton needed then. You basically want to make the original structure rigid either way. Am I wrong.

Could you do a video to cover a roof lift loft conversion, please.

Great video! I’m just wondering how you would get the large beams up in the attic?

Hi Robin, I have a traditional cut pitched roof, in which an internal load bearing wall runs through the centre from gable to party wall. Like in your video, the dormer will be to one side. My architect has indicated that a steel beam would run the length of the roof to support the new floor. Can the internal load bearing wall plate not fulfill this function and enable me to save some height on the pitched side? Perhaps dropping the joists between existing joists, from the centre wall plate to the purlin support?

Thank you for the video

Thank you for the video

Wow ❤

Surely the easiest way to resolve the issue of spreading is to “A”, fit perlins to the gable ends if the roof. “B”, ensure that the rafter cross-section is increased to accommodate wind sheer and the weight of any snow (for the given location with an appropriate margin of safety).

What software was used in this video at the beginning?

Excellent demo video.

Hi mate, thanks for the calculations and the tables. I wonder if you can help me though…I am tying to calculate a roof that’s 6.5 wide with the centre being 4.5 long. I have done the sums and I am getting a figure for Z being around 90. I have worked out that I would need quite a substantial flitch beam from another of your videos. I have decided that a box profiled beam is my best and i think that I have worked out that a 160x80x6.3 is sufficient but cannot find a definitive F value. Do you have a video that you can point me in the direction of please?

I believe the Approved Docs (England) allow the headroom to be reduced to 1.8m instead of 2.0m under the ceiling above the stairs on a loft converstion.

Also putting in purling rafters help

Great videos. If I were to do the calculations as stated, would I still need a structural engineer to come and inspect it or would these calculations be sufficient to show building control officer before they sign off?

Can you add a dormer to this type? If so how?

Very nice ideas. Personally I don't mind losing headroom for an attic/loft. That's to say nothing of code but not that I care much lol

How would you calculate hip length if one end of roof is splayed, i.e the triangle is not symmetrical? Thank you.

This explains a lot we had a crack in the pointing that kept coming back after repointing ,log story short the ceiling developed a large 6ft sag in one corner as the house was 200 year's old I just assumed it was a quirk of an older building ,fast forward the sag collapsed bringing down half of the ceiling on inspection after taking down the old ceiling it turns out the loft joists had come off the perlings it was quite incredible that the joists used were only 1.5 inch by 3.5 inch but I suppose lofts in house's 200 year's old weren't meant to be loaded with junk! they had been attached with old handmade 6 inch nails ,we sistered the old joists and changed a couple and re attached back to the perlings with more modern fixings and reborded and plastered the ceiling I'm going to repoint the crack and fingers crossed that will solve the problem .boy was it a messy job 14 ft by 16 ft room and the plaster was a good inch thick packed with horse hair and lath .I'm wondering was it the weight of the plaster and the pressure from above that caused it all ....

Love the channel, thanks so much!

Yes, very well explained 👍🔨📐

0:30m i need already 210cm. Housing and carseven as bikes are made to small or far to big. Uniform is a group who collects data to change these regulations to adjustable dimensies for the small and big born people......

Scissor truss anyone?

I think I'll stick to open beam ceiling. Makes a triangle.

Just install a dormer

Very interesting. I have been considering a way to do this in a garage.

I’m shopping an old home right now where you can see plain as day the same considerations taken to make habitable space access into the old attic. There is an oddly shallow dormer on the rear roof that surrounds just the attic staircase, to add code-compliant headroom when reaching and exiting the top of the stairs. No windows in the dormer walls, just a couple of (leaking) skylights above.

That pressure is on one set of rafters actual load is spread over the length of the building.

Why not put in a switchback stair?

Hi Robin, have you got any info on fixing either end if the beam to the existing building and new gable end. Would BI need to see a pad stone on tbe gable end? Is the existing end fixed to diagonal wall plates in some way?

The beam doesn’t have to be steel. It just needs to be a sufficient beam which any Engineer would be responsible to incorporate the proper beam. Your test is not including the two end Support walls that hold up the beam so this test is irrelevant and not to be taken seriously.

Excellent video, very informative but.. It's a bit unfair with the "cowboy loft storage companies".. We do quite a bit of work in both truss roof houses and older hand cut roof houses. When we offer to do the job properly by ensuring there is more strength in the exsisting ceiling the cost goes up and we almost always loose out to other firms.. If we just offer the customer a timber raise and slap some boards on top we normally win the job. People only seem to care about how much it costs, wether or not it's safe doesn't come into it!! You wouldn't belive the amout of people we quote that say "cant you just nail the boards the the joists?" or "why raise the floor when you can just cut out of the joists for cables". Clearly we refuse but that's what we have to deal with with our customers. I've been in more truss roof houses than I'd like to mention where the owner, or worse, the actual builder, has cut through trussess to fit the loft hatch in then they complain that their ceiling has cracked!!! The market (IE the customers) push companies to do a "cowboy" job becasue they just don't want to pay to do it properly.

Sir regarding single point loading in a beam test would you please show me the area of bearing of of a timber in a timber testing.

??????....whats a steel ridge beam going to accomplish?

Use a spiral staircase.

Flitch plate 2x10 or 2x12 ridge depending on the length of the ridge and load on the roof or a lambeam ridge Cross walls or walls at right angles off the walls the birdsmouth ties into and collar ties also windbracing on the under sides of the rafters if its to be a covered rafter ceiling Decorative box beams could also hide high tension cables in some circumstances

You should also point out that you should never used screws to construct a roof because in a very short period of time they're going to snap with the little movement of roots

This experiment is kind of naff and in no way scientific, all your variables and scales are very incorrect and uncontrolled. The weight needs to be scaled and applied over the entire roof not just you pushing on the peak, roof timbers are normally deeper and fixed in a way to reduce flexing and rotation so the forces are directed differently. Most domestic traditional roof work is very over engineered so this isn't even a real problem unless your doing it yourself and dont know roof carpentry. If your making a small roof with undersized timbers say for a large shed then make your own trusses with ply gussets or gangplates and they will be good enough.

how many degrees does the roof

Hi Robin, would it be possible to have the model for this? Very infomrative.

No mention of fire safety at all? It's a different situation for a 3 storey house

I didn't kno that

Make a ridge beam instead of board and make it load bearing directly under each end. Solid beam like a sawmilled tree. Dovetail the beam and rafters together.

You would have to have a solid ridge beam completely supported and notch it and the rafters to lock them together where they can not pull apart. Never stick frame that but never say never altogether though.

Stupid. It doesn't matter what the ridge beam is made of. It's the strength of the rafters at the point of the ridge that matters and/or whether the walls are buttressed where the rafters rest on them. This type of "ridge pole" construction is absolutely not the way to make a vaulted ceiling except where the walls are solidly buttressed against spreading. It's perfectly fine to have 2x12 rafters overlap each other to form the ridge and have glue and multiple screws attaching them with blocking in between them to finish the ridge, but best practice is to have the vaulted ceiling located where the walls the rafters attach to are solidly buttressed against the spreading of the rafters.

Not quite sure how the steel ridge beam helps, is it because it transfers the load to the end walls (which are not shown in the model) ? Thanks

With so many (so obviously) opposed to the steel ridgebeam idea, and the meticulous well thought out and edited video regarding load transfers, you almost think that the creator is trying to teach the opposite point: that by removing the ceiling attachment and adding a laminated lvl or steel ridge beam can make the roof to wall connections weak and lead to wall-pushing