Buying a home is a major investment.

If you’ve been looking at properties that were constructed before 1930, there’s a possibility these buildings may have some kind of foundation issues.

Here are four things to look for when searching for older real estate:

1.doors and windows that stick: while this may not sound like a huge issue–let alone a deal breaker–when the doors and windows of the property begin to stick, this could mean that there are bigger problems with the foundation of the house. Whether the structural supports of the base are poorly spaced or rotted, both can be expensive to repair and/or remove.
2.Unrivaled / Sloping floors: When walking around, if you encounter uneven or sloping floors, this should be a big red flag. This implies, first of all, that the home is not perfect. The underlying causes can range from cracks in the property’s foundation to serious damage, rotting or settling, to its supporting structures (such as its posts, piers, girders, joists, or even its base).

3.Cracks in the walls above the doors and windows of the building: if cracks in these areas tend to be increasing in length and/or width, this may also be a sign of damage to the base. It is important to note how easy it is to cover these types of cracks with quick repairs, so if you see fresh paint or other repairs in these places, make sure you ask the agent what work has been done at home and why.

4.Foundation cracks: eventually, after you have checked the interior and exterior of your building, ask to see the basement or crawl space of the structure. If you see any cracks in the walls, be sure to contact a foundation inspector to check the spot. Foundation repair firms, such as Weinstein Construction, will perform a thorough inspection before you purchase the property.

Weinstein Construction is a Los Angeles Foundation survey, foundation builder and foundation repair specialist. Weinstein Construction has inspected more than 75.000 buildings, partnering with engineering firms and local construction and safety authorities. Over the last five years, the company has made more foundation repairs in Los Angeles than any other business in the country.