Consumer confidence in the housing market is growing overall, but the gap between those that say it's a good time to buy versus selling a home is widening, according to Fannie Mae.

Fannie's Home Purchase Sentiment Index rose 1.2 points to 88 in August, due primarily to the good time to sell and mortgage rates expectations components of the index. The HPSI is up 3 points compared to the same time last year, and just below the all-time high of 88.3 set in June.

The August edition of the study found that 36% of respondents said now is a good time to sell, up from 15% of respondents a year ago and 28% in July. However, only 18% of respondents said it is a good time to buy, down from 34% a year ago and 23% in July.

Residents continue to cite high home prices as the most significant reason behind the bad time to buy and good time to sell indicators.

"In the early stages of the economic expansion, home selling sentiment trailed home buying sentiment by a significant margin. The reverse is true today," said Doug Duncan, senior vice president and chief economist at Fannie Mae, in a press release.

"The net good time to sell share is now double the net good time to buy share, with record high percentages of consumers citing home prices as the primary reason for both perceptions. Such a sizable gap between selling and buying sentiment, if it persists, could weigh on the housing market through the rest of the year."

The share of consumers that expect home prices to go up increased by one percentage point, while those anticipating mortgage rates will go down also increased by 4 percentage points.