If you're a home buyer sitting on the sidelines for the deal of the century, you may be kidding yourself. That dream home you're waiting to buy when the housing slump is over is likely to be smaller, plainer, and more expensive later than today's homes.

Why? Homebuyers want homes to be less expensive, but what they don't know is that building costs are about to skyrocket.

According to the National Association of Home Builders, some costs associated with building are going down because of lower demand for housing, like labor, gypsum, insulation and lumber. But any material associated with oil is shooting up. In other words, there's a bubble in PVC pipe.

Buyers think time is on their side because demand is currently suppressed by fear, plummeting home prices, and tighter credit. That's created up to 11 months of standing inventory waiting to be sold.

But when that inventory's gone, look out.

"It doesn't take an economist to see that when we start building again, lumber, gypsum and labor will be more expensive," says Bernard Markstein, senior economist and director of forecasting for the National Association of Homebuilders.

Builders will build to the market and that means they'll be looking for ways to cut the price of homes. Get ready for even smaller lots, less square footage and fewer luxury materials like Italian marble and Brazilian cherry hardwoods.

So should you buy a new home now or wait?

Let's see what history tells us. More square footage took off with the baby boomers. In 1978, median square footage for new homes was 1,650 square feet. The oil embargo and subsequent recession of the 1970s resulted in smaller homes being built between 1979 and 1982. Square footage grew again in '85 and fell in '95, after the recession of the early 90s.

Home sizes in 2006 set a record high of 2,237 square feet. Since then homes have lost value, credit has tightened limiting the number of buyers, and jobs have been lost. That spells smaller housing with fewer bells and whistles.

Markstein says square footage numbers aren't out for 2007 yet, but he says median square footage will be down, and it's certain to be down in 2008. So if you really want that free swimming pool, now's the time.