DETROIT (AP) _ A Denver hotel is the latest company seeking damages from Dow Chemical Co. over a mortar additive that the company once marketed as a strengthener for brick walls - but that plaintiffs say actually causes them to crumble.

Trial began this week in the Executive Tower Inn's lawsuit, which seeks $190 million in actual and punitive damages from Dow for the effects of the additive Sarabond, which Dow marketed from 1965 to 1976.

The hotel suit is one of 28 pending cases involving Sarabond, which has been used in structures ranging from hospitals, college dormitories and zoo structures to the Eisenhower Memorial Tunnel in the Rocky Mountains west of Denver. A number of other suits have been settled out of court. Plaintiffs contend Sarabond corrodes metal supports, letting bricks fall or entire walls sag.

But Dow Chemical argues that brickwork can deteriorate for many reasons, and contends that its corporate wealth - $16.68 billion in 1988 revenues - makes the chemical giant a ''deep pocket'' target for lawsuits.

''We do remain convinced that Sarabond is not deficient. We are back in the courtroom this week defending our position,'' Dow spokeswoman Terri McNeill said from the company's Midland headquarters.

Only two suits have gone to trial before the Executive Tower case that opened Monday in Denver. Juries found Dow liable in both, although the company is appealing one verdict.

A 1979 complaint by Central National Bank in Cleveland, Ohio, resulted in a $28 million damage award and later was settled for $13 million.

A jury awarded St. Vincent's Hospital in Indianapolis $1.7 million in actual damages and $5 million in punitive damages in a judgment that Dow is appealing.

New court actions continue cropping up.

Bronson Methodist Hospital in Kalamazoo filed suit last month, claiming that Sarabond-mortared brickwork on a service-elevator tower built in the early 1970s was deteriorating. Bronson asks unspecified damages in excess of $10,000.

Attorney Bill Dorigan of Minneapolis, who represents the Executive Tower Inn, Bronson Hospital and other Sarabond plaintiffs, has said the mortar additive releases chloride similar to road de-icing salt.

Metal supports strapping the mortared brickwork to the building walls or frame corrode, bricks or sections of wall crack and loosen, and in some cases bricks have fallen, Dorigan said.

He said he knew of no resulting injuries or structural damage to the buildings in question.

Sarabond, made of saran latex, was intended to make mortar as strong as the bricks that it joins. It also was intended to render mortar less permeable by air and water, which would help prevent rust on embedded metal.

Dow sold the Sarabond business in 1976 to St. Louis-based Masonry Systems International, which stopped marketing the product in the early 1980s. McNeill said Dow sold the business because Sarabond was unprofitable.

Dow maintains the mortar additive didn't cause the problems that led to the lawsuits, McNeill said.

The company used Sarabond in its own Midland headquarters buildings as recently as 1981 with no problems, she said.

Dorigan disputed that, in an interview prior to the Executive Tower Inn trial. He said he visited the Dow headquarters twice - after obtaining court orders in two previous lawsuits - and found rusted metal and cracked bricks both times.

Dorigan said more than 20 other suits have been filed that never came to trial. Dow wouldn't comment on the number of suits settled or the total amount of the settlements.

''There have been settlements over the years,'' said McNeill. ''They are not an admission of liability. Where we can resolve suits amicably we do our best to accomplish that.''