Rafters

[Sandy]

I've noticed some manufacturers will have different build standards or quality among the homes they build. How much of a difference is there a home that is build with rafters with 24 O.C. or 16 O.C.? I would imagine by common sense, the rafters on 16 O.C. would be better. What problems could the 24 O.C. cause?

[jgn]

Most well built homes have 16" centers on joists and walls. By going with 24" centers you are expanding the support width by almost 1/3. Problems that could occure are a saging ceiling and joints that split. A lot of companies use 2x3 for the rafters and one company uses a grid work for support. It seems like very few companies advertise what size and spacing joists are but that is a good question to ask. Also check if they use felt as a roof underlament and what pound. I have a check list of questions that I use because it is hard to remember who has what and they are not going to offer information about something that is important that they don't have. I interviewed one company and when I asked if they offer tape and bed walls they said yes but it is an option (salesman knew that answer) when I asked if 3/8 or 1/2 he coughed (it was 3/8).

[rmurray]

Both the roof sheeting and the cieling drywall are very weak when laid flat like the roof and cieling is...The forces of gravity over time can and often do cause cielings and roofs to sag over time on homes with 24 inch centers.....

Is this a problem...well not really a structural problem..but most folks do not like the look of wavy cielings or roofs...

The best construction will have 16 inch centers on the floor joists, wall studs (both exterior and interior) and roof rafts...Then these will be integrated (sometimes called integrated construction) so that for each floor joist there will be a wall stud directly above..then a cieling rafter lined up with these...Then joist, studs and raft are strapped together every 16 inches..giving you a complete wrap of lumber every 16 inches..