To use home equity or not...?

[Jonny Morris]

We bought for about $363k. Put down 80k on the house to avoid mortgage insurance. We have now put about 50k into developing an apartment above garage as our "1st property" rental. The area is growing so I assume it will have risen accordingly with our developments. Recent city valuation puts house value about 60k+ from what we bought at. Question: I would like to use equity from our home to pursue a second investment. My wife sees this as a second mortgage. Any advice, numbers or light anyone can shed on my scenario?