Estimating the cost of building a new home is difficult, but you can get a decent ballpark figure if you have a good idea about the floor plan and materials you want before choosing a contractor.

Q: I inherited a small but buildable lot in a nice community from my late mother, and I now would like to build a house on the land. What do construction costs average today? How can I go about estimating my own costs?

A: Construction costs currently average between $95 and $150 per square foot, according to B4UBuild.com, a company that provides floor plans and other information for people who are planning to build a new house. You probably can keep your own costs down near the lower end of the spectrum if you settle for basic building materials, but expenses can soar quickly above $150 or even more than $200 a square foot if you instead want expensive tiling, fancy cabinets or the like.

Your construction costs also will depend on the actual shape of the new home. As a general rule, the simpler the floor plan, the lower your costs. Rectangular or square homes minimize the needed amount of lumber and save on labor charges for framing. More elaborate plans that include things like fancy outcroppings or vaulted ceilings drive the cost up because they require extra materials and additional framing time.

A couple of Internet sites and inexpensive retail software programs are available to help you assemble rough estimates of your planned construction project. One of the better Web sites is www.Building-Cost.net, which can provide you with a free estimate based on factors ranging from the quality of materials you want to use to the cost of permits and related items that you’ll need to obtain from the city or county.

Once you have figured out how much you’re willing to spend, call at least three contractors and ask each one for written bids on the job. Also, check out their insurance coverage and licenses with state regulators, contact your local Better Business Bureau to see if they have any complaints on file, and make sure you ask for references so you can call their previous customers and set up a time to look at each builder’s work.

After you have settled on the contractor, you can sit down with him or her and decide which changes you might need to make to keep your construction costs within the budget that you established earlier. Good luck, and happy building!

Q: What is a “brokers’ caravan”?

A: It’s a group of brokers and real estate salespeople who get together each week or so to visit – in other words, “caravan” – homes that have been listed for sale recently.

It is important for prospective sellers or their agents to host a caravan soon after they list a home for sale because it’s one of the best ways to informally advertise the property to all the salespeople who work in the area.

Q: The Internal Revenue Service recently sent me a letter saying that I am being audited for both my 2004 and 2005 income-tax returns over some mortgage-interest payments that I deducted for the loan on my own home and some other write-offs I took on a small rental property that I sold a few years ago. I prepare my own taxes, but both of the returns that I need to fight the audit were lost when a thief broke into my car last month and stole my briefcase that held the documents inside. How can I get copies of these past tax returns?

A: If you had used an accountant to help complete your returns, you simply could call his office and ask for copies because most professional tax preparers keep records of their clients’ tax filings for several years.

However, because you filed the returns yourself, you’ll need to contact the IRS directly to get the returns that you need. You can order complete copies of each return for $39 apiece from the agency’s Web site, www.irs.gov.

Also, if you don’t plan to hire an accountant or tax lawyer to help defend against the audit, that same site provides lots of information about do-it-yourself appeals.