Climate Change

[Jaybar]

Concrete is cheaper, faster to install, and generally lasts longer. That's going to be a tough battle to fight.

There are also some applications where timber won't work, but I'm sure there isn't anyone arguing to remove concrete completely from the industry. Well, there probably are some people arguing that somewhere.

Steel framed buildings and heavy timber structures are cheaper when considering material and labor. Concrete's benefits are numerous, though. However, conventionally reinforced concrete fails -- a lot -- and the maintenance costs on those structures is not a joke.

In the end it is up to the developer and architect to decide on a structural system, and hopefully the market shifts with global awareness of material environmental effects.

[Salodin]

Were not giving up concrete and metal lol. Were gonna have to just make up that 10% elsewhere.

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[Salodin]

When I build that super tall building in my metropolitan area, I want it make out of concrete and metal. I dont want my wood structure going higher than like 3 stories. Even wooden rollercoasters suck. No thx.

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[Tokitoki]

Hempcrete is biodegradable and non-structural. Won't work for foundations or similar applications where concrete could be used. The material itself is also more expensive than concrete per CY and generally is less productive than using standard concrete. It's mostly used as an infill material between timbers as it provides good insulation, especially when a plaster is spread over the exterior. It can be exposed to weather, but it is generally recommended that a plaster is applied.

Basically, concrete has a lot of applications where hempcrete can't be used and won't be replaced by hempcrete unless they can find other ways around these limitations.

[Tokitoki]

Steel framed buildings and heavy timber structures are cheaper when considering material and labor. Concrete's benefits are numerous, though. However, conventionally reinforced concrete fails -- a lot -- and the maintenance costs on those structures is not a joke.

In the end it is up to the developer and architect to decide on a structural system, and hopefully the market shifts with global awareness of material environmental effects.

Sorry, had the page open and didn't refresh.

Timber can only be used so much, and you rarely, if ever at this point, see purely steel buildings on a larger scale. If you're talking about residential buildings, or even small apartments, you can use timber and steel framing. No argument.

As far as cost of steel versus cost of concrete, I'd have to take a look at some of our recent pricing. Concrete hovers around $130/CY in NYC for A-40 structural concrete. The price of a raw steel plate per lb is cheaper than concrete delivered per lb, but that doesn't take into account the actual cost of fabricating the steel into the size/type of beams that you need plus delivery.

[Tokitoki]

Keep in mind, steel weights 450pcf where concrete weighs 150pcf. So while the price per lb of steel is cheaper, the price per cf is higher.

[Jaybar]

When I build that super tall building in my metropolitan area, I want it make out of concrete and metal. I dont want my wood structure going higher than like 3 stories. Even wooden rollercoasters suck. No thx.

We've come a long way in heavy timber design! It's even safer in a fire than steel structures. They also look beautiful - check out Cross-Laminated Timber.

Sorry, had the page open and didn't refresh.

Timber can only be used so much, and you rarely, if ever at this point, see purely steel buildings on a larger scale. If you're talking about residential buildings, or even small apartments, you can use timber and steel framing. No argument.

As far as cost of steel versus cost of concrete, I'd have to take a look at some of our recent pricing. Concrete hovers around $130/CY in NYC for A-40 structural concrete. The price of a raw steel plate per lb is cheaper than concrete delivered per lb, but that doesn't take into account the actual cost of fabricating the steel into the size/type of beams that you need plus delivery.

Is that also taking into account cost/weight and erection of reinforcing steel? I'm assuming we are discussing cast-in-place. I know we don't do pure steel anymore especially with super-talls (fire and all that), and I'm not shilling for pure steel either (maybe for CLTs, but ironically I work with historic masonry, so I can only dream).

[Salodin]

Gonna need A LOT of farm space for all that timber...finally a use for the dakotas!

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[archibaldcrane]

I didn't realize BG had so many construction nerds, carry on gentlemen.

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[Jaybar]

Gonna need A LOT of farm space for all that timber...finally a use for the dakotas!

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Canada finally pulling its weight.

[6souls]

Canada finally pulling its weight.

Until it gets tariffed for exporting too much timber to the US.

[Tokitoki]

We've come a long way in heavy timber design! It's even safer in a fire than steel structures. They also look beautiful - check out Cross-Laminated Timber.



Is that also taking into account cost/weight and erection of reinforcing steel? I'm assuming we are discussing cast-in-place. I know we don't do pure steel anymore especially with super-talls (fire and all that), and I'm not shilling for pure steel either (maybe for CLTs, but ironically I work with historic masonry, so I can only dream).

My comment about the price of steel? No, it doesn't account for erection or reinforcement in concrete.

A raw steel plate is around $.34/lb, no fabrication, no delivery.
A-40 concrete delivered in NYC is about $.94/lb.

The cost for reinforcing a concrete slab or column would vary depending on the size of the slab/column and the load it carries, so estimating an exact price for reinforcement is difficult.

A 20' of #5 epoxy coated rebar costs about $11 at $.53/lb. You'd need larger rebar for large columns and slabs, but I don't do superstructure work. Even a #8 rebar is just under 100 lbs.

It's those large columns that are killers and most of the time beams get encased in concrete anyway. Superstructure work is srs bisnis.

EDIT: Regarding CIP versus Precast, you'll generally get better pricing precast, but you'd have to work about connections with the system as a whole and freight. Columns are going to be CIP, but you can definitely do precast floor slab systems which would cut down costs. If you have a large volume of slab pieces that are all the same size, and the precast guy has to do minimal form work because of that, they can crank those things out quick and will give you a decent rate because their labor costs are lower than with small, intricate formwork.

[Tokitoki]

Laminates are actually some interesting shit. I used to do materials testing for a laminate and composites company. I would prepare samples with different skins, fiber glass, carbon fiber, copper wire, and one time we did kevlar. I'd normally use resins, I forget exactly what kind at this point, and would prepare the samples for different tests. Peeling, compression, three point loading, etc. Their clients were mainly wind turbine companies, but also have some small airplane manufacturers, boats, and I think one round of testing was for Lockheed.

We'd use either composite or balsa cores for the laminates. The company actually owned balsa wood farms in South/Central America, I believe mainly Equador and Peru? One time I was testing a large laminate beam, I think it was 6" thick balsa core with about a 1/2" of lamination on each time. I didn't prepare these samples, so I'm not sure exactly what the laminate was comprised of. I'm talking to the lab super as the three point loading test is going and the beam explodes. Thank god for the shields on the testing apparatus because it sent pieces of balsa shooting into the shields. Scared the shit out of us.

[zoobernut]

This aspect of construction and its effect on climate change is legit one of the most interesting things I have read on BG in a while. An actual productive conversation. I find the use of laminates and composite materials fascinating. I know that per weight wood is a much better building material than a lot of people realize but I didn't know that they could make it that much better. What is the environmental cost of making the laminate beams though? I imagine those epoxies and other binding agents can't be that good. Plus they are probably harder to reuse or recycle than steel right?

[Salodin]

Man I feel like epoxies are super bad to mass produce lol

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[Tokitoki]

The resins and/or catalysts we used in our samples were carcinogens. They were definitely not good for the environment. One of my first tasks when I came on was getting rid of all the old shit. I was set up on the factory floor with 30 buckets of old resin and 2 fireproof cabinets full of old chemicals and things to get rid of. I was basically dumping old shit from the cabinets into the buckets of resin and setting the resins to cure so they could dispose of everything with a contaminated solid waste facility.

One of the buckets I had put in a fire retardant paint in, added the catalysts, and started on the next bucket. After a few minutes the resins get very hot to start the curing process. Well, the fire retardant paint was on the verge of catching fire from the heat of the resin and started spitting smoke out of the resin, cracking and whistling as the resin hardened.

Another instance of me being scared shitless working at that lab.

Old resin isn't being recycled. It's being disposed of.

[Jaybar]

There is still research being done to provide non-toxic laminates and sealers. There's an entire red-list of materials that are trying to be phased out. I'm not up to speed on where we are on this, but I know that exposed wood structures in some environments (like Portland) heavily rely on weather protection and sealers to prevent rot.

[Byrthnoth]

Idk, but I do know that we could go a long way towards decarbonization before we had to deal with any of the borderline intractable problems like concrete and long distance travel that get brought up.

[Cail]

Trump Serves Notice to Quit Paris Climate Agreement

https://nyti.ms/33qAvO5

[Cail]

E.P.A. to Limit Science Used to Write Public Health Rules

https://nyti.ms/2CxNwt0