A comprehensive spreadsheet of the specific materials you would use in your rehab is the way to go.Home Depot has a canadian version.http://www.homedepot.ca/for specialty items amazon has alot.http://www.amazon.caYou can also speak with private suppliers in your area.

Should I use the purchase price as the numerator or total acquisition cost: meaning purchase price+closing costs+renovation costs+cost to list?

Debt is the numerator, income is the denominator:  DTI = debt payments / income.2) Now, look at the rentals. 

I guess this is because certain other suppliers have taken a big chunk of the market away?

@Brad Larsen what if you have an online payment system in place and the tenant uses that system to pay, however there was a numerical input error when the tenant enter their account number, so after the 2 or 3 days processing we discover that was the issue and they resubmit the payment and it goes through.

I have had a similar situation and permanent fixes require numerous solutionsRe-grade the lot, install gutters and get the water away from the foundation, Dig around foundation and install drains leading to a sump, pump the water away from the foundation.Adding new drain lines around the foundation can be done by digging around the outside of the entire foundation or by cutting the concrete floor around the interior parameter and adding the lines leading to a sump.None of this will prevent the storm drain from backing up as that is caused by exterior issues related to the city storm system.

The cost of installation will be dependant on numerous items such as:-how many will be installed, how much jacking needs to take place and at how many points, is it a basement or crawl space, will they be installed on concrete or will post pads have to be dug and poured, is it a one or two story house (how much load will each post have to carry), etc. 

@Cody Barrett, another possibility for this is if the shingles are not all from the same "batch" some roofing companies and suppliers will offer a discount if they have small amounts of shingles left form different batches, it is technically the same color but when they are made at different times sometimes the color could be slightly different. 

They make special product for this but you need to go to supplier and not abig box store.  

The price, selection, and speed all beat my local supplier... but something about ordering $10k worth of hardwood flooring off a website has me freaked out.