Trusses vs Stickbuilt

[sharage71]

Gentlemen,

the shop in question is 24 x 30. My dilemma is trusses vs stickbuilt.
I have a rough quote for trusses at 1600.00. Doesn't fit my budget like I would like it to. How can I run the 2 x 6 ceiling joist the span of 24'?
Could I finger joint 2 together then screw/nail bracing on both sides of the joint? In general what would an inspector say. Definately cheaper from what
I calculated on wood cost. Trusses are easier but I'm a total cheapskate.

 

[Sundowner]

Gentlemen,

the shop in question is 24 x 30. My dilemma is trusses vs stickbuilt.
I have a rough quote for trusses at 1600.00. Doesn't fit my budget like I would like it to. How can I run the 2 x 6 ceiling joist the span of 24'?
Could I finger joint 2 together then screw/nail bracing on both sides of the joint? In general what would an inspector say. Definately cheaper from what
I calculated on wood cost. Trusses are easier but I'm a total cheapskate.

at 24 feet, you're in wood I-beam style floorjoist terroitory, and probably something in the 12-14" deep range, at that. 2x6's will NOT work.

if you want to avoid trusses, you're also going to need a serious LVL ridge beam and some beefy collar ties.

 

[sharage71]

I know that this sounds crazy but my father has a 20 x 30 stickbuilt. Will the braced **** joint / finger joint be that weak? He has 2 x 6 ceiling joists and 2 x 6 roof rafters.
They're braced with 2 x 4 kickers and small collar ties. We get next to nothing on the snow load. Damn I'm a cheapskate.

 

[1967mgbgt]

I just purchased a batch of 6/12 "storage" trusses (20 lb/PSF design) for a 24 x 36 that I'm building for just under $900.00. Other places quoted from $1175.00 to $1350.00You might want to shop around a bit more. Unless you have an unusual design or specs, $16.00 sounds a a bit steep.

 

[sparky1562]

I just had some 28ft 5/12 sissor trusses made and it cost me about $ 65 each, delivered. $ 100 each for 24 ft span sounds high if they are 2x4.

Did you have a truss company quoate it or someone like Home Despot?

 

[sharage71]

thank you gentlemen for your guidance. That was the first place I called and it was a truss company. I'll check with Home Depot / Lowes to see what they have to offer and they were 2 x 4's. I would like to have scissor trusses for the extra headroom. That might be why it was higher. This is a great forum !!

 

[hawkeye2]

Scissor Trusses were cheaper than regular trusses when I bought them for my 30x40 shop about 4 years ago. just over $900.00 from a truss company.

Definatly easier and faster than bulding your own!!

 

[rwhite692]

Trusses all the way

 

[GSSFC]

at 24 feet, you're in wood I-beam style floorjoist terroitory, and probably something in the 12-14" deep range, at that. 2x6's will NOT work.

if you want to avoid trusses, you're also going to need a serious LVL ridge beam and some beefy collar ties.

Ceiling joists are different than floor joists. No need to go that big with ceiling joists.

Tim

 

[hidollartoys]

You should check the International Residential Code(IRC) to deternime the size and the spacing for ceiling joists. This could save your life and the contents of your garage. Attic loading can be taken into account if there is any. You should remember that materials used in the past are not the same as those available today. Lumber is not lumber. 2x10s on 12" ctrs will probably be ok but it depends on lumber species and roof/attic loading.

Trusses are "engineered" and will provide you with a superior building with less material. I would get more quotes.

 

[protouring72]

how much more headroom can you gain with scissor trusses? Say I were to build a 30x40 with an 8foot ceiling, how high would it be near the center of the shop?

 

[idoine in toronto]

You didn't mention if your roof has a slope or is flat, but assuming it is has a slope with a central ridge splitting the span in half you may be able to get by with 2x6 joists at 16" o.c.. As mentioned above you need to check the IRC or whatever code is in effect in your area.

Don't take my word for it, you'll need to verify w/ local bldg dept.

 

[rsanter]

I think the only way you can go that span is steel beams, wood beams, OSB wood 'I' beams or trusses (unless you want a couple of poles in the middle of the shop)
I think the trusses are the better way to go

bob

 

[sparky1562]

how much more headroom can you gain with scissor trusses? Say I were to build a 30x40 with an 8foot ceiling, how high would it be near the center of the shop?

it depends on the roof pitch. My roof pitch is 5:12, span 27 ft. I just changed out 5 standard trussses with 5 scissor trusses and gained 2 1/2 ft in the center. Call a truss manufacture and give them your specs and they can run the design for you.

 

[wayne]

GO TRUSSES!!!!! I just finished a 24 x 28 shop with ten foot sidewalls, scissor trusses I used are 4 in 12 rise on the outside, 3 in 12 on the inside. Gives me a 13 foot high center (trusses span the 24 foot side). Up here in Winterland they cost 105.00 each...roof goes on in less than 1 day (we must be related, I am a cheapskate too!)

 

[BooUrns!]

Unless you're an experienced framer, ante up and buy some trusses. You can't be a cheapskate all the time, especially when you're investing in your own property.

 

[hidollartoys]

According to the 2006 IRC the max span for Select Doug Fir 2x6 is 20'8" on 12" centers. This is based on a ceiling live load of 10 lbs/sq ft. Remember that joist span is not the same as rafter span. Joist span is the total distance actually spanned by the joist. Rafter span is measured along the horizontal projection of the rafter which for common rectangular or square buildings is 1/2 the width of the building. To narrow this down based on the joist span tables you should use 2x10 on 12" centers of any grade and species of lumber or 2x10 on 16" centers of any species #2 or better lumber. this is based on a 10lb/sq ft live load. For 20lb/sq ft you will need #1 or select 2x10 of doug fir, hem fir, or southern pine on 12" centers; or select grade only of doug fir or southern pine on 16" centers.

Now the problem it to find this lumber in 24' lengths. This will be tough AND expensive. I would expect the joists to cost 30 to 50 dollars a piece depending on size and grade. Your best most cost effective way to go is trusses.

 

[arbee]

I built mine with attic trusses. 32' clear span with a 16' room above. Pics in my sig.

 

[Matti]

I bought 26' span trusses this summer. The way it was explained to me, the std run of the mill truss will be your best bet cost wise. Around here that is a 4/12 truss. They were around $1200/set. The moment you make changes to the design the cost nearly doubles as mine were $2000 for a tray ceiling/vaulted design mixed with some attic trusses. I really doubt that you can duplicate these designs building them yourselves. The store bought trusses are built in jigs. I have looked at stick built designs but they are using larger wood and engineered beams. I can't imagine you will save much money if any at all. If you want a raised roof then go with taller walls if possible. I was not willing to stick build and the builders around here were not interested either unless proper drawings were done which only added to the cost.

 

[burger]

The American Wood Council has span tables available online. They're pretty easy to use. As has been stated earlier, you're probably going to need bigger lumber than what's available to span 24'. It might be better run an engineered lumber beam down the center so you can cut the span down to 12'.

Here's the link to the AWC tables:

http://www.awc.org/technical/spantables/index.html

 

[burger]

PS- You could consider a cathedral ceiling. Have a look at what I built for my garage.

 

[idoine in toronto]

Sharage71, you didn't mention if your roof design has a slope, but assuming it does you should be OK with 2x6 framing as the span = the horizontal projection of the member taken from top plate to the ridge beam. This will give you a cathedral ceiling, and as burger shows you could also include collar ties. If you plan on insulating the roof, the type of insulation you go with will also have an impact on the depth needed.

This said I don't know whether the material cost will outweigh the labor cost in your area or if you are building yourself when comparing stick to truss construction.

 

[sharage71]

The cathedral ceiling would be fine. I don't have a problem in building it that way. At the end of the day will the inspector let it pass as safe. Burger, was your bldg inspected? Do you have more pics of your build? If I build cathedral style I can work at my own pace and budget plus timing of help from family and friends. From what I understand about local codes I have a year to complete it without applying for another permit.
Yes it will have a slope design. I'm thinking 5/12 pitch. Thanks for the input guys.

 

[idoine in toronto]

Here is a photo from a 22' wide addition I recently designed. Although not a garage it is similar in construction and was designed to accommodate a heavy snow load. In this case I used with 2x10s to get the insulation space I needed.

You will need to have your plans approved before you are issued a permit. Your building department should be able to advise you if what you want to do meets their requirements.

 

[rwhite692]

24 x 36

10' walls

13'6" at the interior peak

 

[hidollartoys]

I believe his original question was about ceiling joists not rafters. Two very different animals. A cathedrial ceiling will eliminate the joists but will require collar ties. If that is not acceptable then he will be required to install a "ridge beam" and that will have to be an engineered member, steel or LVL. If the choice is a ridge beam then the Gable walls will have to be constructed with adequate support and if the doors are in the gable end then allocation will have to be made for that situation. The ridge beam will require uninterrupted support to the foundation.

 

[sharage71]

From the picture of Burger's garage it looks like the ridge beam is a standard 2 x 8 or maybe 2 x 10. It doesn't look to beefy.

 

[hidollartoys]

A ridge beam is designed to support the rafters and does not require the need for a top wall tie: IE ceiling joists. Burger built a truss. Essentially rafters with rafter ties and additional diagonal bracing. His is a "ridge board" not a ridge beam. I dont know if his trusses are engineered or a self design. The 2006 IRC states: The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

Hc/Hr - Rafter span adjustment factor

1/3 - 0.67
1/4 - 0.76
1/5 - 0.83
1/6 - 0.90
1/7.5 or less - 1.00

Hc = Height of joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

The farther you locate the rafter ties above the walls the more you derate the rafter span thus requiring a larger roof rafter.

Burger's idea of a center load carrying beam down the center of the garage is a good idea. However, you stated that this was about doing it on the cheap. I am sorry but this is a "pay me now or pay me later" situation. Structurally if you remove material in one area you will be required to add it someplace else. Engineered trusses are the best way to minimize cost and insure adequate structural design.

 

[Matti]

I made a bunch of inquiries about getting raised tie trusses built (a truss with collar ties)which would eliminate stick building and give the added ceiling height. No one would do it. This leaves me puzzled as to how people get permits to stick build these with no rafters.

 

[burger]

Sharage71,

Sorry if my posts were a little confusing. My first post suggested that you might consider a support beam if you want to have ceiling joists. The second post was a picture of my garage and the cathedral trusses that I built.

With the support beam idea, you would install a large beam, likely made from engineered lumber, across the span of two walls. This beam would be directly supported to the ground. The would allow you to use smaller lumber to cover the other direction, as you would be cutting the span in half. I had considered this design, but my zoning board was very much against me building a second floor.

The next post had a picture of my garage. After the second floor gameroom got squashed from my plans, I figured the next best thing would be a cathedral ceiling. I called around for trusses and got stupid-expensive quotes because my idea was not a standard design. At this point I will confide to you that I am a cheap *******, quite possibly the cheapest except for my wife, who is even cheaper yet. So anyway, I did some research, visited the AWC website, read thru the code books, got out my Statics book, and designed some trusses. The rafters are 2x12's and the supports are 2x4's joined together by splice plates made from scrap OSB. It was all very cheap and very strong.

BTW, there is no ridge "beam". What I have is a ridge board. Its sole function is to provide something to nail the rafters into.


Ed

PS- You asked if the structure was inspected. Yes it was, and the inspector bordered on being a ball-buster at times. In a way that made me feel good, as this was my first time building something on this large of a scale, and I'd rather have a thorough inspector catching my mistakes than a lax one.

 

[sharage71]

Burger,

Would you interested in sending me as much info on you build? Length, width, lumber, time frame. So far I like your thinking. I like cheapskates !!

 

[bigdav160]

As mentioned above, 24' lumber is harder to find. My local yard stocks 2x10 and 2x12 to 22'. I haven't inquired about 24' lumber.

I can tell you that where I live, just material cost, trusses are about 4x the price of conventional stick build. But of course we don't get snow and the live load is low.

 

[Spookrider]

Why not build your own. I did, mine were 15' span.
I double 2X4 on the bottom of the Tri. and 2X4 going up. I know it will support 250 pounds with little bounce or flex.
Simple Tri. mine were 2 on the bottom sandwich the two going up and the middle pieces. I use lags for fastner of choice for the tri. and the attachment to the wall at the header. Also ther were alot metal plates and screws was also used during the building.
I found the torx scerew work alot better than philps screws. The insert bit for it was hard to find in a good deal/bulk event the ones sells them you can't find a bulk pack. All you find is two packs at $3. I had to go on line to find Dewalts fifty pack of T-25 at $10.00.

 

[rcleaver]

If you use trusses and live in an area that gets high winds, be sure to use purlins over or between the trusses. I've seen winds cause waves to form in a roof that was stiffened only with sheathing.

 

[ryaninmichigan]

at 24 feet, you're in wood I-beam style floorjoist terroitory, and probably something in the 12-14" deep range, at that. 2x6's will NOT work.

if you want to avoid trusses, you're also going to need a serious LVL ridge beam and some beefy collar ties.

Wow, this is wrong..

 

[KMR Construction]

Wow, this is wrong..

whats wrong with that? To meet load requirements TJI floor joist are your best bet. Probably don't need a LVL ridge though

 

[hidollartoys]

I think you guys should read the International Residential Code. This application is within the scope of dimensional lumber. I think the issue is exactly what requirements the local building codes officials will require. Snow load should not be the issue in Tenn. unless you are in the mountains but there is probably a minimum design requirement to met. I would suggest that any type of system that is used be adequately designed to met that requirement.

 

[BooUrns!]

whats wrong with that? To meet load requirements TJI floor joist are your best bet. Probably don't need a LVL ridge though

I think the main problem with that suggestion (other than it being very expensive) is that it defeats the purpose of a DIY roof solution. In my area at least, no one will sell you I-joists without an engineered set of drawings. These guys don't want to expose themselves to litigation in the event someone incorrectly applies their product.

I recently tried to purchase a 25' piece of lvl to act as a ridge board for my 24' rafters on a stick built roof. The estimator from my lumber supplier got back to me and told me their design dept would only sell me a 4-ply lvl ridge beam. I imagine it would have weighed over 500lbs, nevermind the ridiculous cost. Obviously these guys had no idea what a ridge board was but this illustrates some of the issues that can arise when trying to use engineered building products outside their specific domain of use.

Apply the span tables and you should be ok, if it's a 24' span one way, a gable roof out of dimensional lumber could easily be used. Don't try to DIY 2x4 trusses if the span tables call for larger pieces. Trusses are engineered to carry specific loads and the price of a truss packages includes the engineers stamp neccessary to pass inspection.

I think the main arguement against this person's attempting to do a stick built roof is that, if he had to ask how to build it, he doesn't have the required skills to build it properly. No offense but there is a certain point where the DIY'ers should realize that some jobs are best left to the professionals. Either stop and take the time to acquire the knowledge & skills or go buy a truss package.

 

[Spookrider]

I totally agree to that, you can get all the tools to do a project. But if you don't have the basic knowledge to apply the tool correctly and safely. What good are the tools to you and stuff around you? Also, what good have apply to your problem when you lack the knowledge to do it right the first time. Then your are dealling three problems money, time, and money.
Sorry for being hash but, it is some what true to what your dad said long time ago can apply to this thought.

 

[Skyline]

How about a completely different perspective on this?

Lightweight wood trusses are the worst thing possible from the perspective of protecing your contents in the event of a fire. If all you're doing in your garage is storing your cars, that's one thing. But if you're doing serious mechanical work, and especially welding, the possibility of a small fire does go up quite a bit. The burn time for these light weight trusses is VERY short (relative to stick built,) before they collapse. You could probably add quite a bit of fire protection with sheetrock, but I know building inspectors around here who insist on double layers of heavy sheetrock for home garages as soon as they know either a lift or welders are going to be used.

As a fireman, I can tell you that we are very cautious about interior fire attacks if there are lightweight trusses involved. Once they are going pretty good, it becomes a case of "surround and drown". If even one small part of a wood truss is comprimised, the whole thing is coming down. Wooden I beams are just as bad. If you do insist on using these things, why not add a sprinkler system to your budget?